The U.S. Navy located and destroyed two mines linked to Iran in an area of the Persian Gulf Friday near where an American frigate was damaged in an explosion apparently caused by mines Thursday, U.S. military officials said.

Meanwhile, the Persian Gulf "war of the cities" continued with Iraqi warplanes carrying out two bombing raids deep inside Iran and Iran retaliating with missile strikes on the Iraqi port of Basra and nearby cities, the two sides reported.In the gulf, the frigate USS Samuel B. Roberts sighted several Iranian mines in the water and cut its engines just before an underwater explosion punched a hole in its hull Thursday morning, injuring 10 sailors, the Pentagon said in Washington.

Two mines moored on cables to the seabed were sighted in the international shipping lane and destroyed by minesweepers Friday afternoon, the Pentagon said.

"There is strong evidence to support the fact that the mines found today came from the same source as those found on the Iran Ajar," a naval spokesman said, referring to the Iranian minelayer that was attacked by U.S. helicopters in the central gulf in September.

A U.S. government source in Washington said the mines destroyed Friday were identical to those found on the Iran Ajar.

The mines found Friday were believed to have been recently planted because they were "covered with fresh black paint, no marine growth on them," said Navy Lt. Cmdr. Mark Van Dyke, a spokesman assigned to the gulf.

The Navy tug Hunter linked up with the Roberts at 4 a.m. Friday and began towing the frigate toward dry dock in the United Arab Emirates capital of Dubai, the Pentagon said.

The Roberts had been operating under auxiliary power since the explosion Thursday, which injured 10 sailors in the worst incident involving an American vessel in the gulf since Iraqi Exocet missiles hit the USS Stark 11 months ago. The attack on the Stark killed 37 sailors and injured 21 others.

The Roberts left its base at Newport Jan. 11 for a six-month tour of the gulf.