Tensions between the United States and China are heightening, with the Trump administration insisting there is "significant evidence" the virus originated at a lab in Wuhan.
The US has blasted China over its handling of the coronavirus outbreak, saying thousands of deaths could have been prevented if the Chinese government had been more transparent about the disease.
Speaking overnight, Secretary of State Mike Pompeo tried to deflect questions about his recent claim that there was "a significant amount of evidence" that Covid-19 emerged from a Chinese lab.
"They knew. China could have prevented the deaths of hundreds of thousands of people worldwide," he said.
"China could have spared the world a descent into global economic malaise. They had a choice but instead – instead – China covered up the outbreak in Wuhan."
He said intelligence agencies and governments around the world were "trying to figure out the right answer" on the origins of the virus.
"We're all trying to get to clarity," he said. "There are different levels of certainty assessed at different places. That's highly appropriate. People stare at data sets and come to different levels of confidence. Every one of us stares at this and knows the reality. The reality of this came from Wuhan."
His renewed criticism of China's handling of the early stages of the pandemic marks a new rise in tensions between the two countries.
The Chinese and US governments have been exchanging a war of words over the coronavirus pandemic, which has now infected 3.7 million people and killed more than 260,000 worldwide. The US is the hardest-hit country, with over 1.25 million cases and 73,000 deaths.
Beijing also hit back at some of Pompeo's claims during a press briefing and called on the Secretary of State to "show" proof China was responsible.
"He said there was 'enormous evidence', then show us," China's Foreign Ministry spokeswoman Hua Chunying said.
"He has never presented evidence because he hasn't gotten any.
"I think that this question should be left to scientists and medical control experts to answer, and the politicians should not keep lying on this issue for the needs of domestic politics."
She also accused the US of "just threatening or coercing them to help the country to frame China together".
Pompeo also said the World Health Organisation needs to demand an investigation into China's handling of the outbreak.
The Australian Government has distanced itself from the Trump administration's claim that the virus started in a lab.
Last week Prime Minister Scott Morrison said Australia had seen no "hard evidence" the virus started at the institute.
"What we have before us doesn't suggest that that is the likely source. There is nothing that we have that indicates that is the likely source," he told reporters in Canberra.
"Now, you can't rule anything out in these environments. We know it started in China, we know it started in Wuhan.
"The most likely scenario canvassed relates to wildlife wet markets, but that's a matter that would have to be thoroughly assessed."
The Chinese government targeted the Australian government and media this past week, hitting back at Australian media reports claiming it deliberately concealed evidence of the coronavirus outbreak, and warning it could exacerbate tensions between the two countries.
"Some Australian media and political elites have lost their independent judgment of the country's overall interests and have adopted a US-led approach to smearing China over Covid-19. They are hurting the profound friendship between the two peoples and the common interests that have long coalesced," a report in the Global Times said.
Last week China said Morrison deserved "a slap in the face" for trying to blame the Covid-19 pandemic on the communist state, warning any push for an independent inquiry into the virus' origins will spark a travel and trade boycott.