The U.S. government will share the majority of its donated Covid-19 vaccine doses through COVAX, the World Health Organization-led program that provides shots to countries in need, the White House announced Thursday.

The Biden administration has committed to donating at least 20 million doses of Covid vaccines produced by Pfizer–BioNTech, Moderna and Johnson & Johnson as well as 60 million doses of AstraZeneca’s vaccines, which has not yet been authorized for use in the United States.

The U.S. plans to allocate 75% of the vaccines through the COVAX global vaccine sharing program, the White House in an email. Of the first 25 million doses, about 6 million will go to countries in South and Central America, 7 million to Asia and 5 million to Africa, the White House said. About 6 million will go to neighboring countries and U.S. allies.

At least 25% of shots will be kept for immediate U.S. needs and for “countries in need, those experiencing surges, immediate neighbors, and other countries that have requested immediate U.S. assistance,” according to the plan.

The administration is donating the shots to “save lives” and thwart the emergence of new variants,  national security advisor Jake Sullivan said Thursday.

“The United States is not doing this as some kind of back-and-forth deal where we are getting something in return,” Sullivan said at a White House briefing. “We are giving these for a single purpose. It is the purpose of ending this pandemic.”

The announcement comes as world leaders urge wealthy nations such as the U.S. to donate Covid shots to other countries. While the U.S. has returned to some form of normality as more Americans get vaccinated and new cases fall, other countries, like India, have experienced huge outbreaks.

Just last week, the WHO said Africa needed at least 20 million doses of AstraZeneca’s vaccine within six weeks to get the second round of shots to people who have received the first.

The head of the Coalition for Epidemic Preparedness Innovations told Reuters that leaders of the Group of 7 rich nations must donate shots urgently to avoid an outcome akin to the 1918 flu pandemic, which killed 50 million people.

“It’s a moral imperative if we want to avoid situations like Peru, if we want to avoid impacts that could rival those of the 1918 flu, we must send vaccine to countries to protect their health-care workers and protect the vulnerable populations now,” Richard Hatchett, chief executive of CEPI which co-runs the COVAX vaccine sharing facility, told Reuters.

In addition to donating the doses, the White House also announced it is lifting restrictions as part of the Defense Production Act that gave the U.S. priority for vaccines developed by AstraZeneca, Sanofi and Novavax.