Philippine police are investigating five U.S. Marines for allegedly raping a woman while in the country for counterterrorism exercises, officials said Thursday.

Philippine authorities briefly delayed the departure of a U.S. warship while searching for the five Marines, who were not allowed to leave the country as scheduled Thursday along with thousands of other American military personnel, said Zosimo Paredes, executive director of a government commission overseeing joint Philippine-U.S. military exercises.

The U.S. Embassy said the United States would fully cooperate with Philippine authorities in the matter.

"The U.S. takes reports of violations of U.S. and Philippine law by U.S. military personnel very seriously," the Embassy said in a statement.

The government expressed concern over the alleged rape, which could provoke fierce condemnation from left-wing groups opposed to the presence of American troops for counterterrorism training with Filipino soldiers.

"The perpetrators of this heinous crime shall be brought to justice," Foreign Secretary Alberto Romulo (search) told a news conference.

Paredes said the five Marines met the Filipino woman on Tuesday in Subic Bay (search), a former U.S. naval base that has been transformed into an industrial and recreational hub north of Manila.

The woman was allegedly raped by the Marines later that night in a still undisclosed place within the sprawling free port, Paredes said.

It was not immediately clear whether the Marines have been charged. But U.S. Embassy spokesman Matthew Lussenhop said he expected charges to be filed soon.

"We're in control of the situation and we're not allowing that this will be whitewashed one way or another," Paredes said.