Hong Kong CNN  — 

Questions surrounding the origins of the novel coronavirus have sparked a war of words between Washington and Beijing – and threatens to worsen already strained relations.

In recent days, US President Donald Trump and Secretary of State Mike Pompeo have doubled down on the assertion that the virus originated from a laboratory in the central Chinese city of Wuhan, where the outbreak was first detected last December.

The claim has unsurprisingly drawn fierce rebuttal from the Chinese government, which on Wednesday described the accusation as “smear” intended to bolster Trump’s reelection chances. But intelligence shared among the Five Eyes network – an alliance between United States and four Anglophone allies, the United Kingdom, Australia, New Zealand and Canada – also reportedly appears to contradict the Trump administration’s assertion.

Here is what we know – and what we don’t know – about the claims and the laboratory at the center of the controversy.

How did China respond?

On Wednesday, China’s foreign ministry called the accusations a political strategy to “smear China” for Republicans ahead of the 2020 election.

“The recently exposed US Republican strategies shows they are encouraged to attack China under the pretext of the virus,” said foreign ministry spokesperson Hua Chunying, adding that China was “fed up with such tricks.”

“We urge the US to stop spreading disinformation or misleading the international community. It should deal with its own problems and deal with the pandemic at home,” she said.

Hua also highlighted the fact that Pompeo did not provide any concrete evidence to substantiate the claim.

“Mr Pompeo cannot present any evidence because he has not got any, this matter should be handled by scientists and not politicians out of their domestic political needs,” she said.

China’s government controlled media has also pushed back at the claims, accusing the US of shifting blame and hurling a barrage of personal attacks at Pompeo. State broadcaster CCTV called him “evil” and “insane,” while state news agency Xinhua called him a “liar.” The Global Times, a nationalist tabloid backed by the ruling Communist Party, said the top US diplomat “has lost his moral compass.”

Beijing has repeatedly stressed that there is so far no conclusion on the origins of the coronavirus, saying the matter should be left to scientists and medical experts to study. It has bristled at calls for an independent international inquiry into the origins of the virus and China’s initial management of the outbreak, painting them as political maneuvers aimed at smearing the country.

The Chinese government has faced criticism at home and abroad over its handling of the virus, especially in the early days of the outbreak. It was accused of silencing whistle-blowers and delaying in informing the public about the severity of the crisis. But it has repeatedly denied any wrongdoing, brushing aside accusations of a deliberate coverup in the critical early stages.

Chinese Foreign Ministry spokesman Zhao Lijian promoted a conspiracy theory on Twitter that the coronavirus was brought to China by the US military.

Chinese officials and state media also pushed unfounded claims alleging the virus did not originate in China. In March, Zhao Lijian, a spokesperson of the Chinese Foreign Ministry, promoted a conspiracy theory on Twitter that the virus had originated in the US and was brought to China by the US military.

Meanwhile, tracing origins of Covid-19 has become a sensitive subject for domestic academic research in China. Last month, the Chinese government imposed restrictions on the publication of such papers, requiring them to receive extra scrutiny and approval from central government officials before being submitted for publication.

What do scientists sa