The White House said Monday that countries and regions including in Asia and Latin America will get coronavirus vaccines as part of the second batch of the 80 million doses the United States has pledged to share worldwide by the end of June.

India and Taiwan, both of which have faced a surge in infection cases in recent months, have been among the recipients of the first 25 million doses. The latest announcement covers the allocation of the remaining 55 million doses.

Millions of doses have already been sent out to the world, including 2.5 million doses that arrived in Taiwan over the weekend, White House Press Secretary Jen Psaki told a press conference.

But she indicated that the United States is having difficulty in following through on President Joe Biden's promise to send all of the 80 million doses to the designated locations by the end of this month.

"What we've found to be the biggest challenge is not actually the supply -- we have plenty of doses to share with the world -- but this is a Herculean logistical challenge," she said, noting the complexities of ensuring needles, alcohol pads and other necessary supplies as well as vaccine storage facilities to maintain the proper temperatures.

Of the 55 million doses, some 41 million will be shared through the U.N.-backed COVAX global vaccine sharing program, with 14 million going to Latin America and the Caribbean, 16 million to Asia, including India, Indonesia, Malaysia, the Philippines, Thailand, Vietnam and Taiwan, and 10 million to Africa.

About 14 million will be shared directly with countries in Asia, Africa and elsewhere, including Gaza, where Palestinians have recently suffered heavy Israeli bombing, according to the White House.

In addition to sharing doses from the United States' own vaccine supply, Biden announced ahead of the Group of Seven summit in Britain earlier this month that his administration will purchase 500 million doses of the Pfizer Inc. vaccine and donate them to 92 low- and lower middle-income countries and members of the African Union.