President Donald Trump said Tuesday he was prepared to enact the Defense Production Act to make sure that Americans had enough coronavirus vaccines.

The president made the remarks as he signed an executive order for American companies to prioritize the distribution of coronavirus vaccines to Americans first.

“If necessary, I told you, we will invoke the Defense Production Act,” Trump said. “But we don’t think it will be necessary. If it’s, it’s a very powerful act as you know.”

The White House hosted an event promoting the success of Operation Warp Speed at developing a coronavirus vaccine in record time.

“This is one of the greatest miracles in the history of modern-day medicine,” Trump said.

Prior to the event, the White House played a highlight video of prominent figures questioning whether a vaccine could get approved and distributed by the end of 2020.

Trump said that he expected that the Food and Drug Administration would authorize the emergency use of the Pfizer vaccine within days. Administration officials have promised to have doses shipped out within 24 hours.

The president urged governors to act quickly to distribute the vaccine, noting that it was their responsibility to care for their citizens.

“The ultimate decision rests with the governors of the various states,” Trump said. “And I hope the governors make wise decisions who will decide where the vaccines will go in their states.”

Trump proposed that the vaccines be sent first to seniors in nursing homes and those working in nursing homes, as well as doctors, nurses, and first responders.

The president estimated that tens of millions of vaccine doses would be available in December, with hundreds of millions more to follow.

“We think by spring we’re going to be in a position that nobody believed possible,” he said.