The United States aims to acquire an additional 200 million doses of COVID-19 vaccines, President Joe Biden said on Tuesday, enough to inoculate most Americans by summertime, as he races to curb a pandemic he warned could still get worse.

Biden’s administration will purchase 100 million doses each of the vaccines made by Pfizer Inc and BioNTech, and Moderna Inc., increasing the overall total doses to 600 million, with delivery expected by summer.

The previous purchase target was 400 million doses.

Each vaccine requires two doses per person to be fully effective, suggesting the new purchases would build up enough of a stockpile to inoculate most of the country’s 331 million people. The vaccines are not approved for use by most children.

“This is a wartime effort,” Biden said in the White House State Dining Room under a painting of President Abraham Lincoln, who led the Union to victory in the U.S. Civil War.

The new purchase target, along with promises to get more vaccine to local authorities, raises the bar for a Democratic president who took office last week with vows to repair what he said was a disastrous emergency response by his Republican predecessor, Donald Trump.

Biden said he would hike the amount of the vaccine going to local governments to 10 million doses per week for the next three weeks, up from 8.6 million currently. The news was welcomed by governors, who said they needed even more doses.