The Biden administration on Thursday announced a plan to share the first 25 million of the 80 million COVID-19 vaccine doses the US intends to distribute abroad.

Of that 25 million, more than 75 percent – nearly 19 million – of the donated vaccines will be allocated to the World Health Organization's global vaccination program called COVID-19 Vaccines Global Access, or COVAX, which purchases and distributes vaccine to low-and middle-income countries. Doses shared through COVAX will be prioritized for Southeast Asian, African and the Caribbean.

The remaining 6 million vaccine doses will be donated directly to handpicked countries, including Canada and Mexico. Overall, the Biden administration said it plans to distribute 80 million excess COVID-19 vaccine doses around the world by the end of the month.

According to the White House, the first distributed 25 million doses only include authorized vaccine from Pfizer-BioNTech, Moderna and Johnson & Johnson.

President Joe Biden said in late April that the US will donate 60 million doses of AstraZeneca's vaccine by July 4, which is still under review by the Food and Drug Administration (FDA). It still not clear when, or even if, the FDA review will be complete and the doses will be cleared.

The administration said Thursday it isn't ready to announce where the 60 million AstraZeneca doses will go, because the FDA safety review is still pending.

"We will continue to donate additional doses across the summer months as supply becomes available," White House coronavirus coordinator Jeff Zients told reporters Thursday.

According to the WHO, the US and other high-income countries have secured almost 90 percent of the available coronavirus vaccine supply.

The US administration was reluctant to send any vaccine doses abroad, saying the extra doses may be backing for potential manufacturing issues, vaccinating children or serving as booster doses against variants of the virus.

"Importantly, we have secured enough vaccine supply for all Americans," Zients said. As of Thursday, 63 percent of American adults have received at least one dose of a COVID-19 vaccine, according to the Centers for Disease Control and Prevention.