The effort has not yet begun, but it has buy-in from senior Biden administration officials and could commence as soon as this month, the officials said, speaking on the condition of anonymity to discuss sensitive military planning. Marines from Camp Lejeune, N.C., have been flown to Bahrain and received related training, with additional Marines due to arrive soon aboard the amphibious assault ship USS Bataan and other ships.

“We have a cohort on the ground,” one of the officials said. He added that the “policy decision has pretty much been made,” although it has not yet received final approval.

The plan, first reported by the Associated Press, is among a set of muscular actions being pursued by the Biden administration following a purported rise in attempts by Iran to seize commercial tanker ships.

On July 5, near the coast of Oman, Iranian forces tried to commandeer two vessels, firing on and striking the hull of one of them, U.S. military officials said at the time.

Such harassment is part of a pattern dating back years and requires an “elevated response,” one of the officials said.

Other recent steps include the deployment of advanced F-35 jets and other fighter aircraft to the Persian Gulf region while adding an additional Navy destroyer to the robust presence of American warships already there.

The Strait of Hormuz connects the Persian Gulf to the Gulf of Oman, and the open ocean beyond. Much of the world’s oil is hauled through the strategic waterway.