President Joe Biden outlined his plan Thursday for the first of 80 million coronavirus vaccine doses that the US will distribute globally, with 75 percent of shots disbursed via the Covax program.

In a fact sheet the White House said that for the doses shared through Covax, Washington would prioritize countries in Latin America and the Caribbean, South and Southeast Asia, and Africa as it aims to help stave off fresh surges of infections.

"We are sharing these doses not to secure favors or extract concessions," Biden said in a statement.

"We are sharing these vaccines to save lives and to lead the world in bringing an end to the pandemic, with the power of our example and with our values."

Biden earlier pledged to export 80 million Covid-19 vaccine doses to countries around the world by the end of this month.

The commitment came amid pressure from other governments to use the United States' large vaccine surplus to help struggling nations now that significant progress has been made in rolling out vaccinations at home.

"The process to export the first 25 million is underway," White House Covid-19 response coordinator Jeff Zients told reporters.

"We will deliver on the president's commitment of 80 million doses by the end of June."

He said the first tranche is coming from the federal supply of doses and will be comprised of a combination of the three vaccines with current US emergency use authorization: Johnson and Johnson, Moderna, and Pfizer/BioNTech.

A vaccine created by AstraZeneca has yet to earn US authorization.

Covax is an international scheme cofounded by the World Health Organization (WHO) that intends to get enough vaccines for 30 percent of the population in 92 of the poorest participating territories -- 20 percent in India -- with donors covering the cost.

'Very appreciative'

According to the US plan, of its first 25 million doses, about seven million are allocated for Asia, especially India, Nepal, Bangladesh, Pakistan, Sri Lanka, Afghanistan, Vietnam, Papua New Guinea and Taiwan.

Some six million are allocated to nations in South and Central America and the Caribbean, including Brazil, Argentina, Colombia, Costa Rica, Peru, Guatemala and Haiti.

Five million are reserved for Africa and will be distributed in coordination with the African Union, National Security Advisor Jake Sullivan said.

"But ultimately, the United States will have the authority to say the doses are going here as opposed to there," he added.

India swiftly expressed gratitude, with Prime Minister Narendra Modi tweeting he spoke with US Vice President Kamala Harris after the announcement.

"I deeply appreciate the assurance of vaccine supplies to India as part of the US Strategy for Global Vaccine Sharing," PM Modi said.

WHO chief Tedros Adhanom Ghebreyesus weighed in to say he was "very appreciative" of Biden announcing the distribution of doses "to protect those most at-risk & for encouraging others to do the same."

Biden said that the remaining six million doses of the initial 25 million will be shared directly with countries experiencing surges or that are in crisis, as well as with partners and neighbors like Canada, Mexico and South Korea.

Sullivan stressed the United States wants to "retain some flexibility" about allocating doses outside the Covax formula as necessary.

Covax has already delivered nearly 80 million doses to 127 territories, with AstraZeneca shots making up 97 percent of doses supplied so far -- the rest being Pfizer-BioNTech.