WASHINGTON (AP) — President Joe Biden declared Monday that the United States and NATO played no part in the Wagner mercenary group’s short-lived insurrection in Russia, calling the uprising and the longer-term challenges it poses for President Vladimir Putin’s authority “a struggle within the Russian system.”

Biden and U.S. allies supporting Ukraine in its fight against Russia’s invasion emphasized their intent to be seen as staying out of the mercenaries’ stunning insurgency, the biggest threat to Putin in his two decades leading Russia. They are concerned that Putin could use accusations of Western involvement to rally Russians to his defense.

Biden and administration officials declined an immediate assessment of what the 22-hour uprising by the Wagner Group might mean for Russia’s war in Ukraine, for mercenary chief Yevgeny Prigozhin or for Russia itself.

“We’re going to keep assessing the fallout of this weekend’s events and the implications from Russia and Ukraine,” Biden said. “But it’s still too early to reach a definitive conclusion about where this is going.”

Putin, in his first public comments since the rebellion, said “Russia’s enemies” had hoped the mutiny would succeed in dividing and weakening Russia, “but they miscalculated.” He identified the enemies as “the neo-Nazis in Kyiv, their Western patrons and other national traitors.”

And Foreign Minister Sergey Lavrov said the special services were already investigating whether Western intelligence services were involved in Prigozhin’s rebellion.

Over the course of a tumultuous weekend in Russia, U.S. diplomats were in contact with their counterparts in Moscow to underscore that the American government regarded the matter as a domestic affair for Russia, with the U.S. only a bystander, State Department spokesman Matthew Miller said.

American diplomats also stressed to Moscow that they expected Russia to ensure the safety of the U.S. Embassy in Moscow and Americans detained in Russia, Miller said.

In a video call between Biden and leaders of U.S.-allied countries over the weekend, all were determined to give Putin “no excuse to blame this on the West,” Biden told reporters at the White House.

“We made clear that we were not involved. We had nothing to do with it,” Biden said. “This was part of a struggle within the Russian system.”

Michael McFaul, a former U.S. ambassador to Russia, said Putin in the past has alleged clandestine U.S. involvement in events — including democratic uprisings in former Soviet countries, and campaigns by democracy activists inside and outside Russia — as a way to diminish public support among Russians for those challenges to the Russian system.

The U.S. and NATO “don’t want to be blamed for the appearance of trying to destabilize Putin,” McFaul said.

A feud between Prigozhin and Russia’s military brass that has festered throughout the war erupted into the mutiny that saw the mercenaries leave Ukraine to seize a military headquarters in a southern Russian city. They rolled for hundreds of kilometers toward Moscow, before turning around on Saturday, in a deal whose terms remain uncertain.

Biden’s national security team briefed him hourly as Prigozhin’s forces were on the move, the president said. He had directed them to “prepare for a range of scenarios” as Russia’s crisis unfolded, he said.

Biden did not elaborate on the scenarios. But national security spokesman John Kirby addressed one concern raised frequently by the public, news media and others as the world watched the cracks opening in Putin’s hold on power — worries that the Russian leader might take extreme action to reassert his command.

Putin and the Kremlin have made repeated references to Russia’s nuclear weapons since invading Ukraine 16 months ago, aiming to discourage NATO countries from ratcheting up their support to Ukraine.

“One thing that we have always talked about, unabashedly so, is that it’s in nobody’s interest for this war to escalate beyond the level of violence that is already visited upon the Ukrainian people,” Kirby said at a White House news briefing. “It’s not good for, certainly, Ukraine and not good for our allies and partners in Europe. Quite frankly, it’s not good for the Russian people.”

In the aftermath of the mutiny, both Prigozhin and Russian Defense Minister Sergei Shoigu made public comments Monday aiming to play down the crisis.

In an 11-minute audio statement, Prigozhin said he acted “to prevent the destruction of the Wagner private military company” and in particular in response to an attack on a Wagner camp that killed some 30 of his fighters.

Biden spoke with Ukrainian President Volodymyr Zelenskyy over the weekend, telling him, ”’No matter what happened in Russia, let me say again, no matter what happened in Russia, we in the United States would continue to support Ukraine’s defense and sovereignty and its territorial integrity.” Biden said. He said he intended to speak with Zelenskyy again late Monday or early Tuesday.

The Pentagon is expected to announce Tuesday that it is sending up to $500 million in additional military aid to Ukraine, including more than 50 heavily armored vehicles and an infusion of missiles for air defense systems, U.S. officials said Monday. They spoke on condition of anonymity because the aid has not yet been publicly announced.

Biden, in the first weeks after Putin sent tens of thousands of Russian forces into Ukraine in February 2022, had issued a passionate statement against the Russian leader’s continuing in command. “For God’s sake, this man cannot remain in power,” he said then, as reports emerged of Russian atrocities against civilians in Ukraine.

On Monday, U.S. officials were careful not to be seen as backing either Putin or his former longtime protege, Prigozhin, in public comments.

“We believe it’s up to the Russian people to determine who their leadership is,” Kirby said.

White House officials were also trying to understand how Beijing was digesting the Wagner revolt and what it might mean for the China-Russia relationship going forward. China and Russia are each other’s closest major partner. The White House says Beijing has considered — but not followed through on — sending Russia weaponry for use in Ukraine.

“I think it’d be fair to say that recent developments in Russia had been unsettling to the Chinese leadership,” said Kurt Campbell, coordinator for the Indo-Pacific at the White House National Security Council, speaking at a forum hosted by the Center for Strategic and International Studies in Washington. “I think I’ll just leave it at that.”

China values Russia as a friend in part to keep from standing alone against the U.S. and its allies in disputes. With Russia’s invasion and resulting international sanctions sapping Russian resources and now sparking a rebellion, McFaul said, Ukraine and its allies could make the case: “‘Xi Jinping, you know, if you want your buddy to stay in power, maybe this is the time to put some pressure on him to wrap up this war.”’

WASHINGTON (AP) — The U.S. Department of Transportation is awarding almost $1.7 billion in grants for buying zero- and low-emission buses, with the money going to transit projects in 46 states and territories.

The grants will enable transit agencies and state and local governments to buy 1,700 U.S.-built buses, nearly half of which will have zero carbon emissions. Funding for the grants comes from the 2021 bipartisan infrastructure bill signed into law by President Joe Biden. The Democratic president has made it a priority to put more electric vehicles on the road — especially for schools and public transit — in an effort to contain the damage from climate change.

“Every day, millions of Americans climb aboard over 60,000 buses to get to work, to school, doctor’s appointments, everywhere they need to be,” Transportation Secretary Pete Buttigieg said in a call with reporters. “These are unprecedented levels of investment when it comes to putting modern cleaner buses on the road.”

Monday’s announcement covers the second round of grants for buses and supporting infrastructure. All told, the U.S. has invested a total of $3.3 billion in the projects so far. Government officials expect to award roughly $5 billion more over the next three years.

The Biden administration said that the new buses will improve public health as diesel exhaust will no longer be going into the air and that the new buses will be easier to maintain.

The government received 475 project proposals for the grants that totaled roughly $8.7 billion, a sign of the demand for the funding.

The Seattle area will be getting $33.5 million to purchase 30 electric battery buses and chargers. The Washington, D.C., transit authority will use $104 million to make a bus garage an electric facility and buy roughly 100 electric battery buses. But money also is going outside of major U.S. cities, with Iowa City, Iowa, and the Seneca Nation in Western New York also receiving grants.

WASHINGTON (AP) — A powerful animal sedative in the illicit drug supply is complicating the U.S. response to the opioid crisis, scrambling longstanding methods for reversing overdoses and treating addiction.

Xylazine can cause severe skin wounds, but whether it is leading to more deaths — as suggested by officials in Washington — is not yet clear, according to health and law enforcement professionals on the front lines of efforts in New Jersey, New York and Pennsylvania. In fact, early data suggests the drug may inadvertently be diluting the effects of fentanyl, the synthetic opioid behind most overdose deaths.

There is broad agreement, however, that much more information is needed to understand xylazine’s impact, to craft ways of disrupting illegal supplies and to develop medicines to reverse its effects.

“We don’t know whether xylazine is increasing the risk of overdose or reducing the risk of overdose,” said Dr. Lewis Nelson of Rutgers New Jersey Medical School, who advises federal regulators on drug safety. “All we know is that there are a lot of people taking xylazine and a lot of them are dying, but it doesn’t mean that xylazine is doing it.”

In almost all cases, xylazine — a drug for sedating horses and other animals — is added to fentanyl, the potent opioid that can be lethal even in small amounts. Some users say the combination, dubbed “tranq” or “tranq dope,” gives a longer-lasting high, more like heroin, which has largely been replaced by fentanyl in U.S. drug markets.

Like other cutting agents, xylazine benefits dealers: It’s often cheaper and easier to get than fentanyl. Chinese websites sell a kilogram for $6 to $20, no prescription required. Chemicals used to produce fentanyl can cost $75 or more per kilogram.

“Nobody asked for xylazine in the drug supply,” said Sarah Laurel, founder of Savage Sisters, a Philadelphia outreach group. “Before anybody knew it, the community was chemically dependent on it. So now, yes, people do seek it out.”

From a storefront in Philadelphia’s Kensington neighborhood, Laurel’s group provides first aid, showers, clothes and snacks to people using drugs.

Xylazine’s effects are easy to spot: users experience a lethargic, trance-like state and sometimes black out, exposing themselves to robbery or assault.

“It’s a delayed reaction, I could be walking down the street, it’s 45 minutes later,” says Dominic Rodriguez, who is homeless and battling addiction. “Then I wake up, trying to piece together what happened.”

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U.S. regulators approved xylazine in 1971 to sedate animals for surgery, dental procedures and handling purposes.

In humans, the drug can cause breathing and heart rates to drop. It’s also linked to severe skin ulcers and abscesses, which can lead to infections, rotting tissue and amputations. Experts disagree on the exact cause of the wounds, which are much deeper than those seen with other injectable drugs.

In Philadelphia, the drug’s introduction has created a host of new challenges.

Naloxone, a medication used revive people who have stopped breathing, doesn’t reverse the effects of xylazine. Philadelphia officials stress that naloxone should still be administered in all cases of suspected overdose, since xylazine is almost always found in combination with fentanyl.

With no approved reversal drug for xylazine, the Savage Sisters group has taken to carrying oxygen tanks to help revive people.

Meanwhile, a roaming van staffed by local health workers and city staffers aims to treat the skin wounds before they require hospitalization.

The wounds can make it harder to get people into addiction treatment programs, which typically don’t have the expertise to treat deep lesions that can expose tissue and bone.

“If you have someone out there who’s ready to come in for treatment, you really want to act on that quickly,” said Jill Bowen, who runs Philadelphia’s behavioral health department.

The city recently launched a pilot program where hospitals treat patients for wounds and then directly transfer them into addiction treatment.

Xylazine can be addictive and patients who stop taking it report severe withdrawal symptoms, including anxiety and distress. There’s no approved treatment but physicians have been using the blood pressure-lowering drug clonidine, which is sometimes prescribed for anxiety.

In April, federal officials declared xylazine-laced fentanyl an “ emerging threat,” pointing to the problems in Philadelphia and other northeastern cities. Testing is far from uniform, but the drug has been detected in all 50 states and appears to be moving westward, similar to earlier waves of drug use.

Officials describe the drug’s toll in stark terms and statistics: Fatal overdoses involving xylazine increased more than 1,200% percent between 2018 and 2021. But that largely reflects increased testing, since most medical examiners weren’t looking for the drug until recently.

“What it is doing is making the deadliest drug we’ve ever seen, fentanyl, even deadlier,” Anne Milgram, head of the Drug Enforcement Administration, told attendees at a recent conference.

But those who have studied the problem closely aren’t so sure.

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One of the only studies looking at the issue reached a startling conclusion: People who overdosed on a combination of fentanyl and xylazine had “significantly less severe” outcomes than those taking fentanyl alone.

It was the opposite of what Dr. Jennifer Love and her colleagues expected, given xylazine’s dangerous effects on breathing. But their analysis of more than 320 overdose patients who received emergency care found lower rates of cardiac arrest and coma when xylazine was involved.

Love, an emergency medicine physician at New York’s Mount Sinai hospital, suggested xylazine may be reducing the amount of fentanyl in each dose. She stressed that this is only one possible explanation, and more research is needed into xylazine’s long-term effects. She also noted that the study didn’t track downstream effects of xylazine that could be deadly, including skin infections and amputations.

But hints that xylazine could be blunting fatal overdoses are showing up elsewhere.

In New Jersey, about one-third of the opioid supply contains xylazine, based on testing of drug paraphernalia. But less than 8% of fatal overdoses involved xylazine in 2021, the latest year with complete data.

Police Capt. Jason Piotrowski, who oversees the analysis of state drug data, said xylazine’s ability to extend users’ high may be a factor in why it’s showing up less than expected in fatal overdoses.

“If xylazine is lasting longer and that’s why people are using it, then they’re not going to need as many doses,” he said. “So now their exposure to the more deadly fentanyl decreases.”

Like other experts, Piotrowski stressed that this is only one theory and xylazine’s impact is far from clear.

Philadelphia officials see no upside to the drug.

“I don’t frankly see a plus side to xylazine,” said Dr. Cheryl Bettigole, the city’s health commissioner. “It seems to increase the risk of overdose and it causes these severe, debilitating wounds that interfere with peoples’ ability to get into treatment.”

Philadelphia’s annual toll of fatal overdoses has climbed by 14% since xylazine became a significant part of the local drug market around 2018. In 2021, the city reported 1,276 overdose deaths. Bettigole expects final 2022 figures to show another increase.

More than 90% of lab-tested opioids in Philadelphia contain xylazine, according to city figures.

Even as Savage Sisters and other advocates deal with xylazine’s toll, they are seeing newer drugs circulate, including nitazenes, a synthetic opioid that can be even more potent than fentanyl.

A shifting mix of opioids, stimulants and sedatives has come to define the U.S. drug epidemic, making it harder to manage a crisis that now claims more than 100,000 lives a year.

The Biden administration and Congress are considering changes to try to limit xylazine prescribing and distribution.

But past restrictions didn’t solve the problem: When regulators cracked down on painkillers like OxyContin, people largely shifted to heroin and then fentanyl.

“First we had pills, then we had heroin and then we had fentanyl,” Piotrowski said. “Now we have everything. And xylazine is just a part of that.”