"The Los Angeles-class attack submarine Newport News left the Arabian Gulf after it successfully completed sea trials in February, proving that the submarine was ready for the approximately 9,000-mile transit back to its home port," U.S. Fifth Fleet commander Vice Adm. Kevin Cosgriff said.

Cosgriff said the Newport News left the Gulf in early March 2007. He said the fast-attack submarine has been replaced by another underwater vessel.

On April 10, Iran said the Newport News was withdrawn after the submarine was found to have leaked radiation and chemicals into the Gulf. In an assertion denied by the Fifth Fleet, Teheran said its protests forced the U.S. Navy to send the submarine home for a complete overhaul.

The Newport News, operating as part of Carrier Strike Group-8, was damaged in a collision with a Japanese tanker on Jan. 8 near the Strait of Hormuz. Over the subsequent weeks, the submarine underwent what was termed temporary repairs to its bow at Fifth Fleet headquarters in Bahrain.

Officials said the sail, mast and reactors of the Newport News were not damaged in the collision with the Japanese tanker. They said the tanker had moved above the submarine, creating a sucking effect that forced the U.S. underwater vessel to surface.

"Safety is always of paramount concern to all professional mariners operating in and around the Gulf," Cosgriff said. "That is why we conducted rigorous sea trials for Newport News in connection with her departure from the Gulf to ensure her return to home port in the U.S. would be safe and uneventful."