The US has withdrawn an invitation to China to participate in the world’s largest international maritime warfare exercise, the Pentagon announced today, citing Beijing’s “destabilising behaviour” in the strategically vital South China Sea, signalling fresh strain in bilateral ties.

Held every two years and based in Hawaii, the Rim of the Pacific exercise (RIMPAC) involves more than 20 countries from across the world, including Australia, India, Japan and the United Kingdom.

The decision to withdraw the invitation to the People’s Liberation Army Navy (PLAN) this summer was made by US Defense Secretary James Mattis in coordination with the White House, according to a US official, after Beijing’s recent deployment of missile systems and the first landing of a Chinese strategic bomber on an island in the South China Sea.

Asserting that the US is committed to a free and open Indo-Pacific, the Pentagon said China’s continued militarisation of disputed features in the South China Sea only serve to raise tensions and “destabilise” the region.

“As an initial response to China’s continued militarisation of the South China Sea, we have disinvited the PLA Navy from the 2018 Rim of the Pacific (RIMPAC) Exercise.

China’s behaviour is inconsistent with the principles and purposes of the RIMPAC exercise,” Lt Col Christopher B Logan said.

The Department of Defense, he said, has strong evidence that China has deployed anti-ship missiles, surface-to-air missile (SAM) systems and electronic jammers to contested features in the Spratly Islands region of the South China Sea.

Logan said China’s landing of bomber aircraft at Woody Island has also raised tensions.

“While China has maintained that the construction of the islands is to ensure safety at sea, navigation assistance, search and rescue, fisheries protection and other non-military functions, the placement of these weapon systems is only for military use,” he said.

China claims almost all of the South China Sea but Vietnam, the Philippines, Malaysia, Brunei and Taiwan have counter claims. The strategic South China Sea is rich in energy reserves, fishery resources and is a busy shipping route.

The Pentagon called on China to remove the military systems immediately and to reverse course on the militarisation of the disputed South China Sea features.

“We believe these recent deployments and the continued militarisation of these features is a violation of the promise that President Xi made to the United States and the World not to militarise the Spratly Islands,” Logan said.

Reacting to the US move as “very unconstructive”, Chinese Foreign Minister and Councilor Wang Yi hoped that the Pentagon would change such a “negative mindset”.

“The Pentagon’s decision on disinvitation of Chinese military in the RIMPAC exercise, we find that a very unconstructive move, non-constructive move. It’s also a decision that’s taken lightly. It’s unhelpful to mutual understanding between China and the US,” he told reporters in a joint news conference with US Secretary of State Mike Pompeo here.

Wang said both the US and China are “big” countries and are “well positioned” to have greater cooperation at the sea. “Mil-to-mil exchanges will help to increase mutual trust. It will also help us to make greater efforts towards world peace and stability,” he said.

On the militarisation in the South China Sea, Wang said, “China is only building civilian and some necessary defence facilities on its own islands”.

“That is the right to self-defense and preservation of every sovereign state. It is a normal deployment and has nothing to do with militarisation, just like the US has a military presence in Hawaii, in Guam,” he said.

Wang said the Chinese deployment was at a “much smaller scale than the US”.

“It’s just out of necessary defense purposes. We don’t hope to see any exaggeration or hype-up of this matter,” Wang said.

China participated in the 2014 and 2016 RIMPAC exercises.

Pompeo said this was an issue of discussion between the two leaders. “I will leave to the Department of Defence to talk about that. Only to say that we have expressed consistent concern about militarisation of the South China Sea. We had a chance to talk about that. And I will leave it to our militaries to talk about their efforts together,” said the US Secretary of State.

China said last week that it landed long-range bombers for the first time on an island in the South China Sea, the latest in a series of manoeuvres putting Beijing at odds with its neighbors and Washington over China’s growing military presence around disputed islands.