The Pentagon has revealed that on late Saturday a Navy submarine and Aegis cruiser collided with each other off the East Coast. 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. during routine operations. 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 said. The Pentagon has launched an investigation into the collision. The news release says "overall damage to both ships is being evaluated," and that the sub's propulsion plant was "unaffected by the collision". Both Navy ships are based at Norfolk, Va. and are operating on their own power, the statement added.