A bill requiring the release of intelligence materials on potential links between the outbreak of the Covid-19 pandemic and a laboratory in the Chinese city of Wuhan has been signed into law by US president Joe Biden.

“We need to get to the bottom of Covid-19’s origins … including potential links to the Wuhan Institute of Virology,” Biden said in a statement. “In implementing this legislation, my administration will declassify and share as much of that information as possible.

“I share the Congress’s goal of releasing as much information as possible about the origin” of Covid, he said.

Biden said that in 2021, after taking office, he had “directed the intelligence community to use every tool at its disposal” to investigate the origins of the virus

That work is “ongoing,” but as much as possible will be released without causing “harm to national security”, he said.

The bill poses political risks for Biden, who is negotiating a difficult relationship with Chinese leader Xi Jinping.

Beijing vehemently rejects the possibility that a leak during research at the Wuhan lab could have unleashed the global pandemic.

However, much of Congress wants to pursue the theory further, and the issue has become a rallying point in particular for Biden’s Republican opponents.

Congress passed and sent the bill to Biden earlier this month.

The Covid-19 outbreak was first detected in 2019 in the eastern Chinese city of Wuhan, leading to almost 7 million deaths worldwide so far, according to official counts, with over a million of them in the US.

But health officials and the US intelligence community remain divided over whether it was spread randomly to humans from an infected animal or leaked during research undertaken at the Wuhan Institute of Virology.

The US Energy Department – one of the US agencies investigating the disaster – concluded with “low confidence” that the virus probably came from a lab, agreeing with the assessment of the FBI, but contradicting the conclusions of several other agencies.