US President Donald Trump on Wednesday touted the use of convalescent plasma as a treatment for Covid-19 and suggested a reported decision by regulators to put on hold an emergency authorization for its use could be politically motivated.

“I’ve heard fantastic things about convalescent plasma,” Trump told a briefing.

An emergency approval by the Food and Drug Administration (FDA) for the use of blood plasma as a coronavirus treatment has been put on hold over concerns the data backing it was too weak, the New York Times reported on Wednesday.

“It could be a political decision,” Trump said.

“You have a lot of people over there that don’t want to rush things because they want to do it after November 3,” he said, referring to the presidential election.

“I’ve heard numbers way over 50% success. And people are dying and we should have it approved if it’s good and I’m hearing it’s good. I heard from people at the FDA that it’s good,” he said.

The FDA did not respond to a request for comment.

People who survive an infectious disease such as Covid-19 are left with blood plasma containing antibodies the body’s immune system created to fight off a virus. This can be transfused into newly infected patients to try to aid recovery.