Millions of doses from U.S. stockpiles of the AstraZeneca's coronavirus vaccine will be sent to Mexico and Canada, the Biden Administration said with an agreement with the two countries expected by Friday.

The White House said the U.S. plans to send 2.5 million doses to Mexico and 1.5 million doses to Canada to help offset their supply shortfall. White House spokesperson, Jen Psaki, said that Canada and Mexico would have to agree to help the country with its supply in future months and return any excess vaccine doses.

"This virus has no borders. We only put the virus behind us if we're helping our global partners," White House officials said.

Mexican foreign minister Marcelo Ebrard said that they are still ironing out the details of the agreement, which should be finalized before the week is over. Ebrard said that Mexico has requested as many vaccine doses as the U.S. can supply.

The U.S.' national vaccination campaign has mainly been using doses provided by Moderna, Pfizer, and Johnson & Johnson. AstraZeneca has yet to apply for authorization from the Food and Drug Administration, which meant that it had millions of ready-to-be-used vaccines in stock stored in the country.

Clinical trials for AstraZeneca's vaccine candidate in the U.S. are currently still underway. In Europe, the vaccine has faced some criticism over its safety and efficacy. At least 18 countries in Europe have temporarily halted the use of the vaccine following reports of it causing unwanted blood clots.

The U.S.'s plan will be its first formal commitment to supplying vaccines to other nations. China, Russia, and India have already sent out vaccines to their neighboring countries.

China recently announced that it would be sending free vaccines to at least 69 foreign countries; a move described by some political analysts as a form of "vaccine diplomacy."

The announcement of the plan comes just days after U.S. President Joe Biden expressed his intention of helping other nations. Biden said that he will first ensure that all Americans will be allocated their doses and if there was a surplus, the country would "share it with the rest of the world."