ABOARD A US MILITARY AIRCRAFT (REUTERS) - US Defence Secretary James Mattis said on Tuesday (May 29) that the United States would continue to confront what Washington sees as China's militarisation of islands in the South China Sea, despite drawing condemnation from Beijing for an operation in the region over the weekend.
Reuters first reported that two US Navy warships sailed near South China Sea islands claimed by China on Sunday, even as President Donald Trump seeks Chinese cooperation on North Korea.
The operation, known as "freedom of navigation", was the latest attempt to counter what Washington sees as Beijing's efforts to limit freedom of navigation in the strategic waters, where Chinese, Japanese and some South-east Asian navies operate.
China expressed its anger, saying it had sent ships and aircraft to warn the US warships to leave.
"You'll notice there is only one country that seems to take active steps to rebuff them or state their resentment (to) them, but it's international waters and a lot of nations want to see freedom of navigation," General Mattis told reporters while en route to Hawaii, where he will oversee a change of command for US Pacific Command.
While the Sunday operation had been planned months in advance, and similar operations have become routine, it comes at a particularly sensitive time and just days after the Pentagon disinvited China from a major US-hosted naval drill.
Critics have said these operations have little impact on Chinese behaviour and are largely symbolic.
Pentagon officials have long complained that China has not been candid enough about its rapid military build-up and using South China Sea islands to gather intelligence.
Recent satellite photographs showed China appeared to have deployed truck-mounted surface-to-air missiles or anti-ship cruise missiles at Woody Island.
Earlier this month, China's air force landed bombers on disputed islands and reefs in the South China Sea as part of a training exercise in the region.
"When they (Chinese) do things that are opaque to the rest of us, then we cannot cooperate in areas that we would otherwise cooperate in," Gen Mattis said.
Gen Mattis said US diplomats were engaged on the issue and he had heard concerns about Chinese actions not just from within the United States government, but also from regional allies.
He will have strong words for China when he travels to Singapore for the Shangri-La Dialogue, a security forum, later this week.
China's claims in the South China Sea, through which about US$5 trillion (S$6.73 trillion) in ship-borne trade passes each year, are contested by Brunei, Malaysia, the Philippines, Taiwan and Vietnam.