LOS ANGELES (AP) — Chinese tech startup DeepSeek said it was hit by a cyber attack on Monday that disrupted users’ ability to register on the site.

The company, whose artificial intelligence chatbot has sent the tech world into a frenzy, said that it had suffered “large-scale malicious attacks” on its services. Registered users could log in normally, DeepSeek said.

DeepSeek began attracting more attention in the AI industry last month when it released a new AI model that it boasted was on par with similar models from U.S. companies such as ChatGPT maker OpenAI, and was more cost-effective in its use of expensive Nvidia chips to train the system on huge troves of data. The chatbot became more widely accessible when it appeared on Apple and Google app stores early this year.

By Monday, DeepSeek’s AI assistant had become the No. 1 downloaded free app on Apple’s iPhone store. The jump in popularity fueled debates over competition between the U.S. and China in developing AI technology. But some U.S. tech industry observers said they were worried about the idea that the Chinese startup has caught up with the American companies at the forefront of generative AI at a fraction of the cost.

DeepSeek was founded in Hangzhou, China in 2023. The company released its first AI large language model later that year.

WASHINGTON (AP) — The CIA now believes the virus responsible for the COVID-19 pandemic most likely originated from a laboratory, according to an assessment that points the finger at China even while acknowledging that the spy agency has “low confidence” in its own conclusion.

The finding is not the result of any new intelligence, and the report released Saturday was completed at the behest of the Biden administration and former CIA Director William Burns. It was declassified and released Saturday on the orders of President Donald Trump’s pick to lead the agency, John Ratcliffe, who was sworn in Thursday as director.

The nuanced finding suggests the agency believes the totality of evidence makes a lab origin more likely than a natural origin. But the agency’s assessment assigns a low degree of confidence to this conclusion, suggesting the evidence is deficient, inconclusive or contradictory.

“I had the opportunity on my first day to make public an assessment that actually took place in the Biden administration. So it can’t be accused of being political,” Ratcliffe told Fox News’ “Sunday Morning Futures.” He said the CIA “has assessed that the most likely cause of this pandemic that has wrought so much devastation around the world was because of a lab-related incident in Wuhan. And so we will continue to investigate that moving forward.”

Earlier reports on the origins of COVID-19 have split over whether the coronavirus emerged from a Chinese lab, potentially by mistake, or whether it arose naturally. The new assessment is not likely to settle the debate. In fact, intelligence officials say it may never be resolved, due to a lack of cooperation from Chinese authorities.

The CIA “continues to assess that both research-related and natural origin scenarios of the COVID-19 pandemic remain plausible,” the agency wrote in a statement about its new assessment.

Instead of new evidence, the conclusion was based on fresh analyses of intelligence about the spread of the virus, its scientific properties and the work and conditions of China’s virology labs.

Lawmakers have pressured America’s spy agencies for more information about the origins of the virus, which led to lockdowns, economic upheaval and millions of deaths. It’s a question with significant domestic and geopolitical implications as the world continues to grapple with the pandemic’s legacy.

Sen. Tom Cotton, R-Ark., chairman of the Senate Intelligence Committee, told “Fox News Sunday” it was important now “to make China pay for unleashing this plague on the world.” He mentioned imposing tariffs or passing legislation that would repeal China’s permanent most favored nation status.

Chinese authorities have dismissed speculation about COVID’s origins as unhelpful and motivated by politics. On Saturday, a spokesperson for China’s U.S. embassy said the CIA report has no credibility.

“We firmly oppose the politicization and stigmatization of the source of the virus, and once again call on everyone to respect science and stay away from conspiracy theories,” embassy spokesperson Liu Pengyu said in a statement emailed to The Associated Press.

While the origin of the virus remains unknown, scientists think the most likely hypothesis is that it circulated in bats, like many coronaviruses, before infecting another species, probably racoon dogs, civet cats or bamboo rats. In turn, the infection spread to humans handling or butchering those animals at a market in Wuhan, where the first human cases appeared in late November 2019.

Some official investigations, however, have raised the the question of whether the virus escaped from a lab in Wuhan. Two years ago a report by the Energy Department concluded a lab leak was the most likely origin, though that report also expressed low confidence in the finding.

The same year then-FBI Director Christopher Wray said his agency believed the virus “most likely” spread after escaping from a lab.

Ratcliffe, who served as director of national intelligence during Trump’s first term, has said he favors the lab leak scenario, too.

“The lab leak is the only theory supported by science, intelligence, and common sense,” Ratcliffe said in 2023.

The CIA said it will continue to evaluate any new information that could change its assessment.