The White House on Thursday laid out a plan for the United States to share 25 million surplus COVID-19 vaccine doses with the world.
It also said it would lift some restrictions to allow other countries to buy US-made supplies for vaccine production more easily.
President Joe Biden said the United States would share the vaccines without expectation of political favours in return.
He has pledged to share some 80 million COVID-19 vaccines internationally this month.
The United States will donate nearly 19 million doses through the COVAX international vaccine sharing programme, he said in a statement.
Through COVAX, some 6 million doses would go to Latin America and the Caribbean, about 7 million doses to South and Southeast Asia and roughly 5 million to Africa.
The remaining doses, amounting to just over 6 million, would go directly from the United States to countries including Canada, Mexico, India and South Korea, he said.
"We are sharing these doses not to secure favours 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."
Although the United States is working through the COVAX facility co-run by the World Health Organisation, the White House retains final say in which countries receive US doses and how many, said national security adviser Jake Sullivan.
The White House will base donation decisions on "factors included achieving global coverage, responding to crises... and helping as many countries as possible," Sullivan said, adding that the United States intends to prioritise its neighbors, including Canada, Mexico and countries in Central and South America.
Biden has come under pressure from the world community to share the US surplus of COVID-19 vaccines.
For months, the White House has remained focused on getting Americans vaccinated after the coronavirus killed more than half a million people in the United States within the last year.
But the president has promised that the United States would become a supplier to other countries and pledged to send abroad at least 20 million doses of the Pfizer Inc/BioNTech, Moderna and Johnson & Johnson vaccines, on top of 60 million AstraZeneca doses he had already planned to give to other countries.
The 25 million doses Biden announced on Thursday will not include supply from AstraZeneca, the White House said.