Speaking to reporters from the White House Sunday, Trump said the FDA has "issued an emergency use authorization... for a treatment known as convalescent plasma."

"This is a powerful therapy that transfuses very very strong antibodies from the blood of recovered patients to help treat patients battling a current infection," Trump said, adding that the authorization will "expand access to this treatment."

"Base on the science and the data, the FDA has made the independent determination that the treatment is safe and very effective," Trump said, before urging all recovered COVID-19 patients in the USA to donate their blood plasma.

White House press secretary Kayleigh McEnany announced Trump’s press conference in a Saturday-night tweet, writing it involved “a major therapeutic breakthrough on the China virus.”

Trump’s announcement Sunday follows White House officials suggesting last week that there were politically motivated delays by the Food and Drug Administration in approving a vaccine and therapeutics for the coronavirus.

The treatment takes convalescent plasma from patients who have recovered from the coronavirus and is rich in antibodies. Though it may provide benefits to those fighting the virus, the evidence has been inconclusive as to how it works or how best to administer it.

The White House has been growing agitated with the pace of the plasma approval. White House chief of staff Mark Meadows did not deal in specifics but said "we've looked at a number of people that are not being as diligent as they should be in terms of getting to the bottom of it."