NORFOLK, Va. – The Pentagon said late Saturday that it is investigating why a Navy submarine collided with an Aegis cruiser during routine operations at an undisclosed location.

The U.S. Fleet Forces Command said in a news release that the submarine USS Montpelier and the Aegis cruiser USS San Jacinto collided at about 3:30 p.m. No one was injured, and the extent of any damage to the vessels was not clear Saturday evening, said Lt. Commander Brian Badura of the Fleet Forces Command.

"We have had circumstances where Navy vessels have collided at sea in the past, but they're fairly rare as to how often they do take place," Badura told The Associated Press.