The Navy submarine and the Aegis cruiser that collided off the coast of northeast Florida are both in area ports and officials are investigating what went wrong, the Pentagon said.

Lt. Cmdr. Brian Badura of the U.S. Fleet Forces Command said in a news release that the submarine USS Montpelier arrived at Naval Submarine Base Kings Bay and the USS San Jacinto arrived at Naval Station Mayport.

The vessels collided at about 3:30 p.m. Saturday off the coast of Jacksonville during routine training operations and no one was injured. The news release said both vessels made it to port under their own power.

"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.

Local Navy officials will not talk about the collision.

IMAGES:  Vessels inspected after collision at sea

The news release said that the sub's nuclear propulsion plant was not damaged, but the cruiser's large sonar dome, located at the base of the ship’s bow, was damaged.

Because the damage to the San Jacinto was below the waterline, divers were in the water Monday morning inspecting the ship.

"These two ships were part a drill preparing for a deployment they were going to be a part of next the summer," said CNN Pentagon reporter Chris Lawrence.

A Navy source told ABC News that three ships were participating in an anti-submarine exercise in preparation for that upcoming deployment as part of the aircraft carrier USS Harry S Truman strike group.

The Montpelier went up to what's known as "periscope depth" Saturday afternoon. During that routine "group sail" off the coast of Jacksonville. It ascended about 200 yards in front of the San Jacinto when an "all back" was ordered. But it was too late.

"We're told initially that the sonar dome underneath the water line of the service ship was damaged, but they're still on board now trying to determine the extent of the damage," Lawrence said.

Navy officials said the collision was under investigation, which could take months, but declined to offer more specifics, including where it happened.

"Most commanders have been relieved of duty, relieved of command for this kind of an offense," Lawrence said. "It will have to be determined whether it was a technical issue who was at fault."

A Navy aircraft carrier and the guided missile cruiser USS Leyte Gulf collided off the East Coast during training operations in October 1996.

In that case, the USS Theodore Roosevelt, based in Norfolk, and the cruiser based in Mayport were about 100 miles off the coast of North Carolina when they collided. Most of the damage aboard the Roosevelt was at its stern, while damage to the Leyte Gulf was limited to its bow above the water line.