WASHINGTON -- The US Food and Drug Administration (FDA) on Sunday authorized the emergency use of blood plasma to treat new coronavirus patients, US President Donald Trump said, calling it a very powerful therapy that he said will save many lives.

"On the therapeutics front, this is what I have been looking to do for a long time. This is a great day. Today I'm pleased to make a truly historic announcement in our battle against the China virus that will save countless lives," he told a White House press conference.

Blood plasma, taken from patients who have recovered from the new coronavirus, is rich in antibodies and thus may help people battling the disease.

The White House earlier suggested there may be a politically motivated delay by the FDA in approving a vaccine and other therapeutics, such as the blood plasma.

"It is only made possible because of operation warp speed," said Trump, referring to the government initiated program aimed at accelerating the development of vaccines and treatment for the novel coronavirus.

The announcement came one day before Trump was set to be formally nominated for the Republican candidate for president on the first day of the Republican Party's four-day national convention.

Trump said the new plasma therapy has been proven to reduce the mortality rate of COVID-19 by up to 35 percent.

Health and Human Services Secretary Alex Azar said a 35 percent reduction in mortality marked a "major advance."

Stephen Han, head of the FDA, noted the emergency authorization did not mean a full FDA approval of the therapeutic treatment but only greater access to the method for the people battling a current infection.

With Sunday's announcement, the US has become one of the first to use the blood plasma on coronavirus patients.

Seoul approved a phase-two clinical trial of blood plasma last week.

South Korea has recently seen a surge in the number of new infection cases, reporting 397 new cases Sunday to bring its total caseload to 17,399.

The US leads the world in both infections and fatalities with over 5.7 million confirmed cases and more than 178,000 deaths so far. (Yonhap)