Washington: The US is planning to begin treating some of the most seriously ill COVID-19 patients with with the antiviral medication Remdesivir, the maker of the drug has announced, as tensions continued across the country over the economic reopening of states.

The medication, recently given fast-track approval for use in the US, could be administered apart from clinical trials as early as Monday to the first coronavirus patients, while manufacturer Gilead is making plans to export it to other nations who give it the green light, reports Efe news.

"We are now firmly focused on getting this medicine to the most urgent patients," Gilead CEO Daniel O'Day told CBS News on Sunday.

"We intend to get that to patients in the early part of this next week, beginning to work with the government, which will determine which cities are most vulnerable and where the patients are that need this medicine."

The California-based Gilead has its "entire supply" of 1.5 million doses of Remdesivir, which could be used to treat "100,000 to 200,000" patients, depending on their various conditions over the next "five or 10 days", O'Day said.

Gilead has accelerated its production of the antiviral and last week said that it was confident it would have "several million" doses available by the end of this year, a supply that could be used for patients in this country and others.

"We've donated the entire supply ... because we acknowledge and recognize the human suffering ... and want to make sure nothing gets in the way of this getting to patients," said O'Day.

The development of Remdesivir, which is administered intravenously, had started in 2009 and was used in Ebola patients during the 2000s via an "emergency authorization" by the Food and Drug Administration.

The experimental therapy will be reserved for patients who are gravely ill, which the FDA defines as needing assistance to breathe, and its distribution will be decided upon by the federal government based on criteria such as the number of beds in intensive care units, O'Day said.

He added that the firm will begin shipping tens of thousands of doses at the beginning of this week and will adjust deliveries depending on how the epidemic evolves in various US cities.

Although some experts warn that there was still no guarantee about the safety of the drug or its efficacy in combating the coronavirus, indications in clinical trials were that it can cut the duration of the illness,.

The US currently accounts for the highest number of COVID-19 cases and deaths in the world.

As of Monday, there were 1,158,040 cases, with 67,682 deaths, according to the Johns Hopkins University.