Donald Trump has slammed the mainstream U.S. media over its sudden about-face on the possibility that COVID-19 accidentally escaped from a laboratory in China, after major outlets rushed to embrace the theory when they originally mocked it as a fringe conspiracy.

'Now everybody is agreeing that I was right when I very early on called Wuhan as the source of COVID-19, sometimes referred to as the China Virus,' Trump said in a statement on Tuesday. 

'To me it was obvious from the beginning but I was badly criticized, as usual. Now they are all saying "He was right." Thank you!' he added.

The lab leak theory, which Trump's administration pushed during his presidency, was long ridiculed as 'disinformation' by a media seemingly intent on discrediting him. 

Now mainstream U.S. outlets are scrambling to backtrack after a year of sneering at the possibility that the pandemic originated as a lab leak - a theory that the Daily Mail has probed since the early days of the global outbreak.  

In recent days, a number of developments have shaken longstanding critics of the lab leak theory, including Dr. Anthony Fauci, who admitted this month that he was 'not convinced' that the virus jumped naturally from animals to humans, as he had previously long insisted.

Circumstantial evidence has long raised questions about the Wuhan Institute of Virology, where researchers were known to be conducting experiments on bat coronavirus strains similar to the one responsible for COVID-19.