0901 GMT September 20, 2017
The badly damaged USS John S. McCain limped into port in the city-state in the afternoon under escort after the dramatic pre-dawn accident, which sent water flooding into the vessel, AFP reported.
A major search involving ships and aircraft from three countries was launched for the missing sailors after the collision with the Alnic MC in the Singapore Strait, near the Strait of Malacca.
Analysts said the accident, so soon after June's collision off Japan involving a US warship, raised questions about whether the US Navy was overstretched in Asia as it seeks to combat Chinese assertiveness in the South China Sea and North Korea's nuclear goals.
The US Navy said there was "significant damage to the hull" of the warship in the latest collision, which led to flooding of crew sleeping areas, machinery and communications rooms.
"Damage control efforts by the crew halted further flooding," they said in a statement after the John S. McCain arrived at Changi Naval Base in the city-state.
A helicopter took four of the injured to a Singapore hospital with injuries that were not life-threatening while the fifth did not need further medical attention, the navy said.
The 505-foot (154-metre) vessel could still sail under its own power after the collision at 5:24 am (2124 GMT Sunday) with the Liberian-flagged tanker, which was slightly bigger at 600 feet. Two other vessels escorted it into port, AFP journalists saw.
The warship had been heading for a routine stop in Singapore after carrying out a "freedom of navigation operation" in South China Sea earlier in August around a reef in the Spratly Islands, sparking a furious response from Beijing.
The vessel is named after US Senator John McCain's father and grandfather, who were both admirals in the US navy.
President Donald Trump initially said "that's too bad" in response to reporters' shouted questions about the collision, as he arrived back at the White House after a holiday.
He followed up with a Tweet: "Thoughts & prayers are w/ our sailors aboard the where search & rescue efforts are underway."
Ridzwan Rahmat, a naval expert at Janes by IHS Markit, said initial indications suggested the US warship may not have been obeying rules designed to separate maritime traffic passing through the Singapore Strait.
With the accident coming soon after the freedom of navigation operation, it raised questions "whether there is crew fatigue setting in, whether or not the tempo of operations by the US Navy in this region is getting too fast," he told AFP.
Singapore, Malaysia and US ships and aircraft were all involved in the hunt for the missing sailors.
The tanker involved in the collision, which was used for transporting oil and chemicals and weighed over 30,000 gross tons, sustained some damage but no crew were injured, and Singapore said there was no oil pollution.
In June seven American sailors died when the destroyer USS Fitzgerald collided with a Philippine-flagged cargo ship in a busy channel not far from Yokosuka, a gateway to container ports in Tokyo and nearby Yokohama.