Seven U.S. sailors are unaccounted for after a Navy destroyer collided with a merchant ship southwest of Yokosuka, Japan, early Saturday local time, a U.S. official and the Navy said.

Some flooding was reported aboard the USS Fitzgerald, a 505-foot destroyer, after the collision with a Philippine container vessel at approximately 2:30 a.m. Saturday local time (1:30 p.m. ET Friday), about 56 nautical miles of Yokosuka, the U.S. 7th Fleet said.

A U.S. official told NBC News that seven U.S. sailors are unaccounted for. Japanese broadcaster NHK earlier reported that seven sailors from the Fitzgerald were missing, citing the Japanese Coast Guard.

“The extent of number of personnel injuries is being determined,” the 7th Fleet said in a statement earlier. The Navy was working with the Japanese Coast Guard to conduct a medevac for one sailor, the Fleet said.

The 7th Fleet said the Fitzgerald experienced some flooding but continues to operate under its own power although its propulsion is limited.

“The full extent of damage is being determined,” The Fleet said.

The Fitzgerald suffered damage to its starboard side above and below the waterline, the Fleet said. A U.S. Navy official said the bridge was damaged in the collision so communication with the ship is limited and difficult.

“US and Japanese support from the Navy, Maritime Self Defense Force and Coast Guard are in the area to ensure that the Sailors on USS Fitzgerald have the resources they need to stabilize their ship,” Admiral John Richardson, chief of naval operations, said in a statement.

Image: USS Fitzgerald Collision

Image: USS Fitzgerald Collision

The U.S. Navy official said the ship was conducting routine operations in Sagami Bay when the collision occurred.

“As more information is learned, we will be sure to share to it with the Fitzgerald families and when appropriate the public,” he added.

The Navy said in a statement that it had requested the help of the Japanese Coast Guard in response to the collision. The USS Dewey and Navy tugs were being dispatched to help, and Navy aircraft were being readied, the Fleet said.

Image: The Arleigh Burke-class guided-missile destroyer USS Fitzgerald is seen off Shimoda

Image: The Arleigh Burke-class guided-missile destroyer USS Fitzgerald is seen off Shimoda