- Coronavirus pandemic
image sourceGetty Imagesimage captionThe impact of the virus is felt around the world, including in the city of its origin, Wuhan
A US intelligence report requested by President Biden into the origins of the coronavirus pandemic is inconclusive, US media reports say.
Agencies are reportedly divided on whether the virus – first seen in China – was the result of a natural spillover from animal to human or was caused by a laboratory accident.
An summary of the report is expected to be published in the coming days.
The pandemic has claimed more than four million lives around the world.
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While countries have been working to contain the spread of the virus, scientists have been trying to work out from where it first appeared in early 2020 in the Chinese city of Wuhan.
A team from the World Health Organization, who visited Wuhan, concluded in a report earlier this year that the disease most likely spilled over from an animal sold at a market.
But its apparent dismissal of the possibility the virus might have leaked accidentally from the Wuhan Institute of Virology, which has studied coronaviruses in bats for more than a decade, has been rejected by some scientists.
In May President Biden gave the US intelligence agencies 90 days to assess the data and produce a report that "could bring us closer to a definitive conclusion" on the virus's origins.
Intelligence that several researchers at the Wuhan lab were hospitalised in November 2019, and China's refusal to allow a thorough investigation into the lab theory, is said to have prompted Mr Biden's decision.
media captionCovid-19 and Wuhan: Why don't we know more?
However, in June, Director of National Intelligence Avril Haines played down hopes of reaching a conclusion, telling Yahoo News: "We're hoping to find a smoking gun, but it might not happen."
Many scientists believe it could take years of research before a definitive conclusion on the virus's origins is reached.
"We should not even be thinking about closing the book or backing off, but rather ratcheting up the effort," David Relman, a Stanford University microbiologist, told the Washington post.
The intelligence report was delivered to President Biden on Monday. White House spokeswoman Jen Psaki said it might take "a couple of days, if not longer, to put together an unclassified version" for the public.