The move is in keeping with the Trump administration's "America first" buzzword towards the global pandemic and raises concerns about what the administration will do if and when a vaccine is developed.

"Imagine this was a vaccine," Liverpool University senior visiting research fellow Dr. Andrew Hill told The Guardian. "That would be a firestorm. But perhaps this is a taste of things to come."

The U.S. has secured more than 500,000 treatment courses of the drug through September, the Department of Health and Human Services (HHS) announced Monday. That amounts to 100 percent of drugmaker Gilead's production for July and 90 percent for August and September.

"President Trump has struck an amazing deal to ensure Americans have access to the first authorized therapeutic for COVID-19," HHS Secretary Alex Azar said in the announcement. "To the extent possible, we want to ensure that any American patient who needs remdesivir can get it. The Trump Administration is doing everything in our power to learn more about life-saving therapeutics for COVID-19 and secure access to these options for the American people."

But the administration's actions will make it harder for people in other countries to access the drug.

"They've got access to most of the drug supply [of remdesivir], so there's nothing for Europe," Hill told The Guardian.

Remdesivir was the first drug to be approved by U.S. licensing authorities to treat the new coronavirus. It is also the only drug currently approved by the European Medicines Agency to treat COVID-19, EuroNews pointed out. It has been shown to reduce the amount of time seriously ill coronavirus patients spend in the hospital from 15 to 11 days. It has not been shown to speed the recovery time of people with mild or moderate cases. There is also no evidence that it increases a patient's chance of surviving, according to The Independent.

The only other drug shown to work against the virus is a cheap and widely available steroid called dexamethasone, which Oxford University researchers said had reduced the risk of death by a third in severely ill patients.

The administration's buy-up announcement came the same day that Gilead said it was pricing remdesivir at $3,120 per treatment course. That announcement also earned the Trump administration criticism, this time for failing to push for a cheaper price for a drug whose development was partly publicly funded.

"Gilead did not make remdesivir alone," Public Citizen's Access to Medicines Program director Peter Maybarduk said. "Public funding was indispensable at each stage, and government scientists led the early drug discovery team. Allowing Gilead to set the terms during a pandemic represents a colossal failure of leadership by the Trump administration."

The decision to buy up most of the drug's supplies through September also follows a pattern of administration actions that have prioritized the U.S. over international cooperation in fighting the virus.

The German government criticized an alleged attempt in March by the U.S. to secure exclusive rights to a coronavirus vaccine being developed by German company CureVac, EuroNews reported.

Then, in May, French company Sanofi said the U.S. would have first access to its vaccine if it proved effective, until criticism from the French government prompted the company to reverse its stance, according to The Guardian.

The Trump administration also asked 3M not to sell N95 respirators to Canada, the company claimed in April, as Global News reported. The masks were eventually allowed to cross the border.

The U.S. continues to lead the world in both coronavirus deaths and cases, at more than 2.6 million cases and more than 127,000 deaths, according to Wednesday morning figures from Johns Hopkins University. Last week, the country broke its record with a daily tally of 40,000 new cases, according to The Guardian. Texas, Arizona, California and Florida have all been forced to reverse reopening plans.

"We are going in the wrong direction," National Institute of Allergy and Infectious Diseases director Anthony Fauci told the Senate, as The Guardian reported. "I would not be surprised if we go up to 100,000 a day if this does not turn around."