WASHINGTON — The White House, besieged with requests from other nations to share its supply of coronavirus vaccine, announced Thursday that it would distribute an initial 25 million doses this month across a “wide range of countries” in Latin America and the Caribbean, South and Southeast Asia, and Africa, as well as the Palestinian territories, war-ravaged Gaza and the West Bank.

The doses are the first of a total 80 million that President Biden has pledged to send overseas by the end of this month. Three-quarters of the initial batch will be given to the international vaccine effort known as Covax, officials said at a White House briefing on the pandemic, though administration officials are helping decide where to send them.

The rest will be reserved for “immediate needs and to help with surges around the world” and regions dealing with “urgent, present crises,” said Jake Sullivan, the president’s national security adviser, including in India, Ukraine and Iraq as well as the West Bank and Gaza.

But the donation is nowhere close to enough. About 11 billion doses are needed to vaccinate 70 percent of the world’s population against the coronavirus, according to estimates from researchers at Duke University. As of last month, the analytics firm Airfinity estimated that 1.7 billion doses had been produced.

Thursday’s announcement comes a week before Mr. Biden leaves for Cornwall, England, to meet with the heads of state of the Group of 7 industrialized nations, where the global vaccine supply is certain to be a topic of discussion. Officials said the Biden administration would donate additional doses throughout the summer as they become available.

“This is just the beginning,” said Jeffrey Zients, Mr. Biden’s coronavirus response coordinator. “Expect a regular cadence of shipments around the world, across the next several weeks.”

While China and Russia have used vaccine donations as an instrument of diplomacy in an effort to extract favors from other nations, Mr. Biden has insisted the United States will not do that — a point that Mr. Sullivan emphasized on Thursday in describing the White House strategy.

Nearly two-thirds of U.S. adults have had at least one shot of a coronavirus vaccine, and the rate of new cases and deaths has plummeted, contributing to an overall picture across the country that is “encouraging and uplifting,” Dr. Rochelle P. Walensky, the director of the Centers for Disease Control and Prevention, said on Thursday.

But the picture around the world, especially in poorer nations in Africa and Central and South America, where vaccination rates are much lower, is bleak. According to data from Johns Hopkins University, Uruguay, Argentina, Colombia and Paraguay are all awash in new cases; in Colombia, nearly 500 people a day have died of the coronavirus over the past several weeks. A sudden, sharp rise in coronavirus cases in many parts of Africa could amount to a continental third wave, the World Health Organization warned on Thursday.

Some African nations have less than 1 percent of their populations partly vaccinated, according to data from the Our World in Data project at the University of Oxford, and the percentages of vaccinated people in Honduras and Guatemala are around 3 percent of the population.

Mr. Sullivan said the administration had decided to give priority to “neighbors” of the United States, including countries like Guatemala and Colombia, Peru and Ecuador, while also working with existing regional networks like the African Union to allow local authorities to allocate the vaccines as they see fit.

Mr. Biden came into office vowing to restore America’s position as a leader in global health, and he has been under increasing pressure from activists, as well as some business leaders, to do more to address the global vaccine shortage. This year, he said he was reluctant to give away vaccine doses until the United States had enough for its own population, though he promised in March to send a total of four million doses of AstraZeneca’s vaccine to Mexico and Canada.

Those doses, it turned out, were made at a Baltimore facility owned by Emergent BioSolutions, where production has since been put on hold after an incident of contamination.

Mr. Biden’s pledge to donate 80 million doses this month involves vaccines made by four manufacturers. Besides AstraZeneca, they are Pfizer-BioNTech, Moderna and Johnson & Johnson, the last three of which have received U.S. emergency authorization for their vaccines.

The president has made several announcements to help reach his goal. He said last month that his administration would send 20 million doses of the authorized vaccines overseas in June — the first time he had pledged to give away doses that could be used in the United States. Officials said Thursday that the number rose to 25 million because more authorized doses have become available.

Mr. Biden also announced last month that he would send one million doses of Johnson & Johnson’s vaccine to South Korea; a plane carrying those doses was expected to take off Thursday evening, Mr. Zients said.

And the president has pledged to donate up to 60 million doses of AstraZeneca’s vaccine. But those doses, also made at the Emergent plant, are not authorized for domestic use and cannot be released to other countries until regulators deem them safe. If they are not cleared for release, Mr. Biden would have to agree to donate more of the three vaccines used here to fulfill his 80 million promise.

The president has described the vaccine donations as part of an “entirely new effort” to increase vaccine supplies and vastly expand manufacturing capacity, most of it in the United States. To further broaden supply, Mr. Biden recently announced he would support waiving intellectual property protections for coronavirus vaccines. He also put Mr. Zients in charge of developing a global vaccine strategy.

But activists say simply donating excess doses and supporting the waiver are not enough. They argue that Mr. Biden must create the conditions for pharmaceutical companies to transfer their intellectual property to vaccine makers overseas, so that other countries can establish their own vaccine manufacturing operations.

Peter Maybarduk, the director of Public Citizen’s Access to Medicines program, called Thursday for the administration to invest $25 billion in “urgent public vaccine manufacturing at sites worldwide” to make eight billion doses of vaccine using mRNA technology within a year, and to “share those vaccine recipes with the world.”

Asked recently whether the United States was prepared to do that, Andrew Slavitt, a senior health adviser to the president, sidestepped the question, saying only that the United States would “play a leadership role” but still needed “global partners across the world.”

On Thursday, Mr. Zients said the United States was lifting the Defense Production Act’s “priority rating” for three vaccine makers — AstraZeneca, Novavax and Sanofi — that do not make coronavirus vaccines authorized for U.S. use. The shift means that companies in the United States that supply the vaccine makers will be able to “make their own decisions on which orders to fulfill first,” Mr. Zients said.

That could free up supplies for foreign vaccine makers, allowing other countries to ramp up their own programs.

Abdi Latif Dahir contributed reporting.