The United States have bought up almost the entire stock of a drug shown to be effective in treating coronavirus patients.
The Trump administration purchased 500,000 courses of drug remdesivir from pharmaceutical firm Gilead.
This represents 100% of the US pharmaceutical firm Gilead's projected production for July (94,200 treatment courses), 90% of production in August (174,900 treatment courses), and 90% of production in September (232,800 treatment courses), alongside an allocation for clinical trials.
What is remdesivir?
Remdesivir was originally created to use against Ebola.
The anti-viral drug has been approved for use in the UK and US, among other, after data suggested it can cut recovery time by about four days.
There is no data yet proving that use of the drug improves survival chances in those living with the virus.
Compared to commonly used steroid dexamethasone, remdesivir is pricey, costing $3,200 for a treatment of six doses.
Fears over fight for vaccine
Oxford University's Professor Peter Horby said manufacturer Gilead would be under "certain political pressures locally" as a US company.
He told BBC Radio 4's Today programme: "It does raise two very important questions: what is a fair price for a drug, and what is fair access to a drug, and those are common issues but are particularly important in a global crisis like this.
"That's part of the fair access question - the trial that gave the result that allowed remdesivir to sell their drug wasn't just done in the US, there were patients participating through other European countries, in the UK as well, and internationally, Mexico and other places.
"And I wonder how they would feel knowing now that the drug is going to have restricted availability in their own country and would they have volunteered for that trial if they had known that?"
It also raises questions if a vaccine is found, he said.
"Commercial companies are built to behave like this and we need a much stronger framework if we are going to develop these things and they're going to be used for national emergencies."