The guided-missile destroyer USS John S. McCain collided with the merchant vessel Alnic MC while heading to Singapore for a routine port call, the Navy said in a statement.
"Initial reports indicate John S. McCain sustained damage to her port side aft," the Navy said. "There are currently 10 sailors missing and five injured."
A search-and-rescue mission was under way involving Singaporean ships, helicopters and tug boats, as well as U.S. Navy aircraft.
The warship was currently sailing under its own power and heading to port, the Navy said, without specifying which port.
The Alnic MC is a Liberian-flagged, 183 meter-long oil or chemical tanker of 50,760 deadweight tonnes, according to shipping data in Thomson Reuters Eikon.
An Alnic crew member contacted later by Reuters by telephone said there was no oil spill from the tanker, which was carrying almost 12,00 tonnes of fuel oil from Taiwan to discharge in Singapore.