A U.S. warship was damaged after colliding with a merchant vessel east of Singapore on Monday, the second collision involving a US warship in just over two months.
The Navy said in a statement the guided-missile destroyer USS John S. McCain collided with the merchant vessel Alnic MC while "the ship was transiting to a routine port visit in Singapore".
"Initial reports indicate John S. McCain sustained damage to her port side aft," the Navy said. A search-and-rescue mission was under way.
In addition to the 10 missing sailors, the Navy said five were injured in the collision.
Search and rescue efforts are under way, the Navy statement said, with helicopters and Marine Corps Osprey aircraft from the amphibious assault ship USS America responding.
Last week the U.S. Navy said that it had removed two senior officers and the senior enlisted sailor on a U.S. warship that almost sank off the coast of Japan in June after it was struck by a Philippine container ship.
Seven sailors died in June when the USS Fitzgerald and a container ship hit each other in waters off Japan.
Singaporean ships and helicopters were also responding, the Navy said.