SHIPS and aircraft from the United States, Indonesia, Singapore and Malaysia joined the search for 10 missing US sailors after the guided-missile destroyer USS John S McCain was in collision with an oil tanker early yesterday.

The warship docked at Singapore’s naval base with significant damage to its hull after the clash east of the island city state with the 600ft Alnic, which was the second in two months involving a ship from the US Navy’s Seventh Fleet in the Pacific.

Four sailors were evacuated by a Republic of Singapore Navy helicopter to hospital for treatment of non-life threatening injuries, naval authorities said. A fifth injured sailor did not require further medical attention.

The McCain had been heading to Singapore on a routine port visit after conducting a sensitive freedom-of-navigation operation last week by sailing near one of China’s man-made islands in the South China Sea.

The Navy’s Seventh Fleet said in a statement that damage to the destroyer’s hull flooded adjacent compartments including crew berths, machinery and communications rooms.

A damage control response prevented further flooding, it said.

The McCain was damaged on its port side aft, or left rear, by the collision but headed to port under its own power.

A photo tweeted by Malaysia’s Navy chief Ahmad Kamarulzaman Ahmad Badaruddin showed a gaping hole in the McCain’s side near the waterline.

Jane’s, a defence industry publication, estimated the hull rupture was 10ft wide.

One of the injured sailors, Navin Ramdhun, an operations specialist second class, posted a Facebook message telling family and friends he was OK and awaiting surgery for an arm injury. He said in a message he could not reveal what had happened, adding: “I was actually sleeping at that time. Not entirely sure.”

The Singapore government said no crew were injured on the Liberian-flagged Alnic, which sustained damage to a compartment at the front of the ship 23ft above its waterline.

There were no reports of a chemical or oil spill.

Singapore sent tugboats and naval and coastguard vessels to search for the missing sailors and Indonesia said it sent two warships. Malaysia said two ships as well as aircraft from its navy and air force were helping with the search, and the USS America deployed Osprey aircraft and Seahawk helicopters.

There was no immediate explanation for the collision, and the US Navy said an investigation would be conducted. Singapore, at the southernmost tip of the Malay Peninsula, is one of the world’s busiest ports and a US ally. Its naval base is regularly visited by American warships.

In June, seven sailors died when the USS Fitzgerald and a container ship collided in waters off Japan.

The Fitzgerald’s captain was relieved of command and other sailors were being punished after the Navy found poor seamanship and flaws in keeping watch contributed to the collision, the Navy announced last week.

An investigation into how and why the Fitzgerald collided with the other ship was not finished, but enough details were known to take those actions, it said.

President Donald Trump has expressed concern for the McCain’s crew after he returned to Washington on Sunday night from his New Jersey golf club.

When reporters shouted questions to him about the McCain, he responded: “That’s too bad.”

About two hours later, Trump tweeted that “thoughts and prayers” were with the McCain’s sailors.

The incident came as the US and South Korea started conducting annual military drills which consistently infuriate Pyongyang, despite appeals to halt the exercises.

Last week, North Korea appeared to back down from a threat to send missiles towards the US Pacific island of Guam, but said it would watch US actions. It has already condemned these drills as pouring “gasoline on fire”.

Washington described them as defensive in nature, but the North sees them as preparation for invasion.

China and Russia last month proposed a halt on military exercises in exchange for a freeze on missile tests.

But General Joseph Dunford, chairman of the US Joint Chiefs of Staff, said the exercises were “not currently on the table as part of the negotiation at any level”.