DUBAI, United Arab Emirates (AP) – A nuclear-powered U.S. Navy submarine collided with a Turkish cargo ship in the Persian Gulf early Monday, the U.S. Navy reported.

Nobody was injured and both ships appeared to suffer only superficial damage, said the spokesman for the U.S. Navy 5th Fleet, Cmdr. Jeffrey Breslau.

It was the U.S. Navy’s second collision with a civilian vessel in the Gulf in 14 months.

The USS Philadelphia was traveling on the surface of the Gulf when it hit the Turkish-flagged M/V Yaso Aysen at around 2:00 a.m. local time, said a statement from the 5th Fleet Headquarters in Bahrain.

The collision happened about 30 miles northeast of Bahrain, said Breslau.

The Philadelphia was conducting surface operations on its way to Bahrain for a scheduled port visit, the Navy said. Afterward, the submarine continued to Bahrain where inspectors will check it for damage.

The submarine’s nuclear-powered propulsion plant was not damaged in the crash, the Navy said.

Breslau said the Turkish ship, a bulk carrier, suffered minor damage to its hull just above the water line.

The ship weighed anchor at the site of the crash and a U.S. Coast Guard vessel was sent to offer help, Breslau said. An initial inspection found the cargo vessel to be seaworthy.

The cause of the collision was under investigation, Breslau said.

The Philadelphia, launched in Groton, Conn., in 1974, has a crew of 125, Breslau added.

The submarine is part of a fleet of U.S. and allied navy vessels conducting what are called “maritime security operations” in the Gulf against the smuggling of weapons and drugs and movement of terrorists.

In July 2004, the aircraft carrier USS John F. Kennedy collided with a dhow in the Gulf, leaving no survivors on the traditional Arab sailing boat.

The Navy relieved the Kennedy’s commander, Capt. Stephen B. Squires, after the incident. The Kennedy itself was unscathed, but two jet fighters on the deck were damaged when one slid into the other as the carrier made a hard turn to avoid the dhow.

Associated Press reporter Adnan Malik contributed to this from Manama, Bahrain.