USA missile destroyer the USS John S McCain collided with vessel Alnic MC at 10:24am NZT (6:24am local time) during a routine visit to Singapore.
The U.S. ship, which appeared to have damage to part of its left rear, is now sailing under its own power and heading to port at the Changi Naval Base in Singapore, the U.S. Pacific Fleet said.
The destroyer McCain's home port is Yokosuka, Japan.
Senator John McCain sent the following message on Twitter in response: "Cindy & I are keeping America's sailors aboard the USS John S McCain in our prayers tonight".
The ship involved in the collision was a Liberian-flagged tanker used for transporting oil and chemicals and weighing over 30,000 tonnes, according to industry website Marine Traffic.
Search and rescue efforts are underway in coordination with local authorities.
McCain collided with the Alnic MC vessel while traveling to Singapore around 6:24 a.m. Monday, the agency said in a statement. The ship is now sailing under its own power and heading to port, it said. It was en route to Singapore from Pyeongtaek in South Korea.
And in late January, the guided-missile cruiser USS Antietam ran aground while trying to anchor in Tokyo Bay.
On May 9, the guided-missile cruiser USS Lake Champlain was struck by a small fishing boat off the Korean Peninsula.
The Chinese military "immediately sent out warships" with two missile frigates identifying the USA naval destroyer and warning it away from Mischief Reef in the Spratly Islands, which China calls the Nansha Islands, according to China's foreign ministry.
The ship's commander, Alfredo J. Sanchez, is a native of San Juan, Puerto Rico.
John McCain, both of whom were onetime U.S. Navy admirals.