Two U.S. warships struck floating mines in the northern Persian Gulf Monday, and the Navy said seven servicemen were injured. Both vessels were damaged but were not in danger of sinking, officials said.

The United States - which reported allied forces have flown 80,000 sorties in the monthlong aerial bombardment of Iraq - said Monday the attacks were continuingThe U.S. military said Monday the United States lost another aircraft in combat, but Air Force helicopters flew 40 miles north of the Saudi border Sunday night and rescued the pilot of the F-16 after he parachuted from his disabled warplane. The pilot was not identified.

The mine damage was the first of the war sustained by U.S. vessels. Struck were a high-tech missile cruiser, the USS Princeton, and an amphibious assault ship, the USS Tripoli, that is part of a 31-vessel task force gearing up for a possible Marine amphibious assault.

Such an invasion could be one element of the ground offensive that allied leaders have indicated is days if not hours away.

Initial reports from the U.S. military about the mine explosions said both vessels remained under their own power after the blasts.

Iraq's navy is all but decimated and thought to pose little threat to the allied armada in the gulf. But U.S. officials believe Iraq has been dumping mines in the waterway. More than 80 mines have been destroyed during the gulf crisis.

The Tripoli, an Iwo Jima-class helicopter and troop carrier, can carry up to a battalion of Marines - more than 2,000 men - and as many as 25 helicopters. Only a small contingent of Marines was reported aboard.

The missile cruiser Princeton, normally part of a carrier group, is equipped with a computer-linked Aegis radar and missile system for long-range air defense, and has a crew of about 360.

The ships were about 10 miles apart when they hit the mines, Marine Brig. Gen. Richard Neal said.

Baghdad radio, meanwhile, said Iraq had inflicted casualties on allied ground troops with a cross-border missile barrage into Saudi Arabia. U.S. military spokesmen reported no such overnight engagement.

During the weekend, American troops were again reminded of the danger of friendly fire. In one of seven border engagements Sunday, a U.S. Apache attack helicopter destroyed two U.S. military vehicles with missiles, killing two soldiers and wounding six, the military said.

Of the 14 Americans killed in ground action to date, 10 have been victims of friendly fire.