MANILA – China’s “aggressive behaviour” in the South China Sea, including the use of water cannon by its coast guard against a Philippine vessel, must be challenged and checked, said the commander of the US Navy’s Seventh Fleet on Sunday.

Vice-Admiral Karl Thomas assured the Philippines of United States backing in the face of “shared challenges” in the region.

“My forces are out here for a reason,” he said.

The largest of the US Navy’s forward-deployed fleets, the Seventh Fleet, which is headquartered in Japan, operates as many as 70 ships, has around 150 aircraft and more than 27,000 sailors.

It operates over an area of 124 million sq km from bases in Japan, South Korea and Singapore.

“You have to challenge people I would say (are) operating in a grey zone. When they’re taking a little bit more and more and pushing you, you’ve got to push back, you have to sail and operate,” Vice-Adm Thomas told Reuters.

“There’s really no better example of aggressive behaviour than the activity on 5 August on the shoal,” he added.

On Aug 5, a Chinese coast guard ship used water cannon against a Philippine boat carrying supplies to troops aboard a warship Manila had intentionally grounded on a shoal in the South China Sea, a fault line in the rivalry between the US and Beijing in the region.

Vice-Adm Thomas said he has had discussions with Vice-Admiral Alberto Carlos, head of the Philippine Western Command overseeing the South China Sea, “to understand what his challenges are to find opportunities to be able to help him”.

“We certainly shared challenges. So I wanted to better understand how he views the operations that he’s responsible for. And I want to make sure that he understood what I had available,” said Vice-Adm Thomas who was in Manila for a port call.

On Saturday, Vice-Adm Thomas said he joined a flight from Manila “to go out and check out the South China Sea”.

The Philippines won an international arbitration award against China in 2016, after a tribunal said Beijing’s sweeping claim to sovereignty over most of the South China Sea had no legal basis.

China has built militarised, man-made islands in the South China Sea and its claim of historic sovereignty overlaps with the exclusive economic zones of the Philippines, Vietnam, Malaysia, Brunei and Indonesia.

The Chinese embassy in Manila did not immediately respond to a request for comment. REUTERS