Washington, US President Donald Trump said the country is stepping up developing treatments for COVID-19 patients, including experiment on antimalarial drug hydroxychloroquine and a blood-related therapy.

Addressing a White House briefing on Sunday, Trump said that hydroxychloroquine is being administered to 1,100 patients in New York along with Z-Pak, which is azithromycin, Xinhua news agency reported.

"It's very early yet. It only started two days ago. But we will see what happens," he said.

The US Food and Drug Administration (FDA) is also allowing the emergency use of a blood-related therapy, called convalescent plasma, as an experimental treatment for seriously ill patients, Trump said.

The therapy involves taking blood plasma from people who have recovered from COVID-19. The sick patients will be transfused with the blood taken to boost their immune systems, according to Trump. The early results are good, he added.

The country is also looking at an approval for sterilization of masks, Trump said.

The United States is unleashing every tool quickly in order to vanquish the virus, he said.

Trump also announced that the federal social distancing guidelines will be extended to April 30. The death rate in the country would likely peak in two weeks, he said.