With the United States closing in on President Joe Biden’s goal of injecting 100 million coronavirus vaccinations weeks ahead of his target date, the White House said the nation is now in position to help supply neighbors Canada and Mexico with millions of lifesaving shots.

The Biden administration on Thursday revealed the outlines of a plan to “loan” a limited number of vaccines to Canada and Mexico as the president announced the U.S. is on the cusp of meeting his 100-day injection goal “way ahead of schedule.”

“I’m proud to announce that tomorrow, 58 days into out administration, we will have met our goal,” Biden said. He promised to unveil a new vaccination target next week, as the U.S. is on pace to have enough of the three currently authorized vaccines to cover the entire adult population just 10 weeks from now.

Ahead of Biden’s remarks, the White House said it was finalizing plans to send a combined 4 million doses of the AstraZeneca Covid-19 vaccine to Mexico and Canada in its first export of shots. Press secretary Jen Psaki said the details of the “loan” were still being worked out, but 2.5 million doses would go to Mexico and 1.5 million would be sent to Canada.

“Our first priority remains vaccinating the U.S. population,” Psaki said. But she added that “ensuring our neighbors can contain the virus is a mission critical step, is mission critical to ending the pandemic.”

The AstraZeneca vaccine has not yet been authorized for use in the U.S. but has been by the World Health Organization. Tens of millions of doses have been stockpiled in the U.S., waiting for emergency use authorization, and that has sparked an international outcry that lifesaving vaccine is being withheld when it could be used elsewhere. The White House said just 7 million of the AstraZeneca doses are ready for shipment.

The initial run of doses manufactured in the U.S. are owned by the federal government under the terms of agreements reached with drugmakers, and the Biden administration has faced calls from allies across the globe to release the AstraZeneca shots for immediate use. Biden has also fielded direct requests from Canadian Prime Minister Justin Trudeau and Mexican President Andrés Manuel López Obrador to buy vaccines produced in the United States.