Despite praising China's coronavirus response and "transparency" in the wake of the outbreak, Donald Trump and White House officials have now accused the country's government of blocking efforts to determine the source of the virus as reports surface that warnings were issued about a coronavirus research lab in Wuhan as early as 2018.

Mr Trump has cast doubt over the country's handling of the outbreak and shifted blame to the World Health Organization amid accusations that his own delayed response to the virus had cost lives after multiple warnings from members of his administration over several weeks were reportedly ignored or dismissed.

White House officials also are mulling whether the virus that causes the Covid-19 disease originated from a lab in Wuhan. Mark Milley, chair of the Joint Chiefs of Staff, said that reports are "inconclusive" while Secretary of State Mike Pompeo echoed the president's claims about China's alleged lack of transparency and suggested a link between a lab and nearby market.

On Tuesday, Mr Milley told reporters: "We've had a lot of intelligence take a hard look at that. At this point it's inconclusive, although the weight of the evidence seems to indicate natural. But we don't know for certain."

A 2018 cable from US diplomats who visited the Wuhan Institute of Virology and obtained by The Washington Post said that findings at the lab "strongly suggest" that a Sars-like coronavirus can be transmitted from bats to humans, underlining the importance of "surveillance of Sars-like coronaviruses in bats and study of the animal-human interface critical to future emerging coronavirus outbreak prediction and prevention."

Scientists cast serious doubt over claims that the virus had "escaped" from or was purposely manipulated in a research setting, a theory promoted by right-wing officials who have claimed that the virus was engineered as a bioweapon.

The "rumour and speculation", as Mr Milley called it, has persisted despite several reports and statements from scientists and researchers who found that the virus's genetic makeup was not lab-created.

Secretary Pompeo told Fox News host Sean Hannity: "We know they have this lab. We know about the wet markets. We know that the virus itself did originate in Wuhan. So all those things come together."

He said that WHO had denied the US access to information from China at a critical early period of the outbreak. But in January, the president said: "China has been working hard to contain the coronavirus. The United States greatly appreciates their efforts and transparency."

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And through February, the president repeatedly said that he spoke with President Xi Jinping and was assured that the country is "working hard" to combat the outbreak.

On Tuesday, the president announced the US would suspend financial support for the WHO after he accused the United Nations agency of "severely mismanaging" the global response and "pushing misinformation" from China's government.

The announcement came a day after he aggressively defended the US response, including his restrictions on travel from China at the end of January, and screened a video to reporters that downplayed the outbreak's impact. He refused to answer whether the administration considered any response to the outbreak in the entire month of February.

Secretary Pompeo also blamed the organisation for the pandemic.