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Sources believe coronavirus originated in Wuhan lab as part of China's effort to compete with US

EXCLUSIVE: There is increasing confidence that COVID-19 likely originated in a Wuhan laboratory not as a bioweapon, but as part of China's effort to demonstrate that its efforts to identify and combat viruses are equal to or greater than the capabilities of the United States, multiple sources who have been briefed on the details of early actions by China's government and seen relevant materials tell Fox News.

This may be the "costliest government coverup of all time," one of the sources said.

The sources believe the initial transmission of the virus was bat-to-human, and that "patient zero" worked at the laboratory, then went into the population in Wuhan.

The “increasing confidence” comes from classified and open-source documents and evidence, the sources said. Fox News has requested to see the evidence directly. Click here for more on our top story

Other related developments:

-Timeline of coverup?

-WHO boss Tedros says he’ll face coronavirus inquiry, vows to ‘learn' from deadly ordeal

-Connecticut’s Murphy says Trump, not China, to blame for virus

China may be conducting secret nuclear tests, State Department says

The State Department is concerned China may be conducting small nuclear tests in secret, possibly violating an international agreement banning such tests, Fox News confirmed Wednesday.

A new State Department report on compliance with arms control, nonproliferation and disarmament, first obtained by The Wall Street Journal earlier Wednesday, found that China may be flouting international law by conducting the tests within the northwest region of the country, using low explosive power.

The report didn't prove any wrongdoing on the part of the Chinese, but still raised red flags.

"Some compliance concerns are raised and some findings of violations are made," it read. Click here for more

Other related developments:

-CNN updates article after being accused of publishing Chinese propaganda

-Behind Bloomberg News' campaign to silence its own journalists on China corruption

-'Significant' coronavirus mutation discovered

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Biden slams Trump for going into public without mask

Former Vice President Joe Biden slammed President Trump for choosing to not wear a face mask during the coronavirus pandemic, saying everyone has “an obligation to be responsible.”

“I don’t walk out of this house without a mask on. I don’t walk out in the yard to talk to Secret Service if I don't have a mask on,” the presumptive Democratic presidential nominee said.

“I wish he would stop talking and let the scientists speak,” Biden said during a virtual town hall from his home in Delaware. Click here for more

-Podcast host who interviewed Biden accuser rips CNN contributor

-Dems on Biden's VP shortlist mum on accusations

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