WASHINGTON—President Biden will tap up to 180 million barrels of government oil reserves to help tamp down near-record high fuel prices, an unprecedented government intervention into oil markets following Russia’s invasion of Ukraine.

In remarks from the White House Thursday, Mr. Biden framed high energy prices as a wartime issue that requires a robust and wide-ranging response. The oil release, about 1 million barrels a day for six months, starting in May, would be the Biden administration’s third, and by far the biggest-ever drawdown from the country’s emergency stockpile of roughly 568 million barrels.