The Covid-19 virus first circulated in Wuhan around November 2019.
New intelligence has prompted the Energy Department to conclude that an accidental laboratory leak in China most likely caused the novel coronavirus pandemic, reported The Wall Street Journal (WSJ).
The shift by the Energy Department, which previously was undecided on how the virus emerged, is noted in an update to a 2021 document by Director of National Intelligence Avril Haines's office.
The conclusion was a change from the department's earlier position that it was undecided on how the virus emerged, reported WSJ.
The update, which is less than five pages, wasn't requested by the Congress. But lawmakers, particularly House and Senate Republicans, are pursuing their own investigations into the origins of the pandemic and are pressing the Biden administration and the intelligence community for more information.
The Energy Department now joins the Federal Bureau fof Investigation in saying the virus likely spread via a mishap at a Chinese laboratory, reported WSJ.
The Energy Department's conclusion is the result of new intelligence and is significant because the agency has considerable scientific expertise and oversees a network of US national laboratories, some of which conduct advanced biological research.
Energy Department's insights come from its network of national laboratories, some of which conduct biological research, rather than more traditional forms of intelligence like spy networks or communications intercepts.
The FBI previously came to the conclusion that the pandemic was likely the result of a lab leak in 2021 with "moderate confidence" and still holds this view.
US officials added that while the Energy Department and the FBI each say an unintended lab leak is the most likely cause of the pandemic, they arrived at those conclusions for different reasons.
The updated document underscores how intelligence officials are still putting together the pieces on how Covid-19 emerged. More than one million Americans have died in the pandemic that began more than three years ago, reported WSJ.
However, the conclusion was made with "low confidence," and came as America's intelligence agencies remained divided over the origins of the coronavirus, reported WSJ.
Four other agencies, along with a national intelligence panel, still believe that the pandemic was likely the result of a natural transmission, and two are undecided.
The Central Intelligence Agency and another agency that officials wouldn't name remain undecided between the lab-leak and natural-transmission theories, the people who have read the classified report said.
US National Security Advisor Jake Sullivan declined to confirm or deny the Journal's reporting in an appearance Sunday on CNN. He said President Biden had repeatedly directed every part of the intelligence community to invest in trying to discern as much as possible about the origins of the pandemic.
"President Biden specifically requested that the national labs, which are part of the Energy Department, be brought into this assessment because he wants to put every tool at use to be able to figure out what happened here," Sullivan said.
The Covid-19 virus first circulated in Wuhan, China, no later than November 2019, according to the US 2021 intelligence report. The pandemic's origin has been the subject of vigorous debate among academics, intelligence experts and lawmakers.
The emergence of the pandemic heightened tensions between the US and China, which US officials alleged was withholding information about the outbreak. It also led to a spirited and at times partisan debate in the US about its origin.
China, which has placed limits on investigations by the World Health Organisation, has disputed that the virus could have leaked from one of its labs and has suggested it emerged outside China.
The Chinese government didn't respond to requests for comment about whether there has been any change in its views on the origins of Covid-19.
However, the fact that Wuhan is the center of China's extensive coronavirus research, has led some scientists and US officials to argue that a lab leak is the best explanation for the pandemic's beginning.
Wuhan is home to an array of laboratories, many of which were built or expanded as a result of China's traumatic experience with the initial severe acute respiratory syndrome, or SARS, epidemic beginning in 2002.
They include campuses of the Wuhan Institute of Virology, the Chinese Center for Disease Control and Prevention, and the Wuhan Institute of Biological Products, which produces vaccines.