The United States will spend $3.5 billion to buy and donate 500 million doses of the Pfizer COVID-19 vaccine to some of the world’s poorest countries.
It has urged other G7 nations to follow suit.
The vaccine donation - the largest ever by a single country - was announced before US President Joe Biden meets leaders of the Group of Seven advanced economies in western England.
A senior Biden administration official said the US is not seeking favours in exchange for these doses and is not imposing conditions - political or economic or otherwise on countries for receiving these doses.
The 500 million doses are destined for the world's 100 poorest countries. A senior Biden administration official described the gesture as a "major step forward that will supercharge the global effort" with the aim of "bringing hope to every corner of the world."
"We really want to underscore that this is fundamentally about a singular objective of saving lives," the official said.
US drugmaker Pfizer and its German partner BioNTech have agreed to supply the United States with the vaccines, delivering 200 million doses in 2021 and 300 million doses in the first half of 2022.
The shots, which will be produced at Pfizer's US sites, will be supplied at a not-for-profit price.
Cardinals are scheduled to meet on Tuesday to plan Pope Francis' funeral, which leaders from around the world will attend ahead of a conclave next month to elect a new head of the Roman Catholic Church.
Russian President Vladimir Putin proposed on Monday bilateral talks with Ukraine for the first time since the early days of the war, and his Ukrainian counterpart Volodymyr Zelenskyy said Kyiv was eager to discuss a halt to attacks on civilian targets.
Ukraine issued air raid alerts for Kyiv and the country's eastern half as blasts shook the city of Mykolaiv early on Monday, authorities said, hours after the one-day Easter ceasefire declared by Russian President Vladimir Putin came to an end.
US Vice President JD Vance began a four-day visit to India on Monday and will hold talks with Prime Minister Narendra Modi, as New Delhi rushes to avoid steep US tariffs with an early trade deal and boost ties with the Trump administration.