US Defense Secretary James Mattis has accused China of "intimidation and coercion" in the South China Sea, taking a tough stance on Beijing at a security summit in Singapore.
On Saturday Mattis spoke at the Shangri-La Dialogue, an annual security summit in Singapore that each year attracts speakers who are the top policymakers in the defense and security community of countries across the western Pacific.
"We do not see it as a militarisation by going through what has traditionally been an global water space", said Mr Mattis of the United States ship movements through the South China Sea.
Mattis's handle in Singapore returned to a theme that he and different senior USA officers have hammered residence since Trump took workplace - that America is right here to remain within the Asia-Pacific area and that allies ought to stick to Washington as an alternative of aligning with Beijing.
The comments came on the heels of a string of events that highlight the tension between the world's two biggest economies over the South China Sea's disputed waters.
He warned that America's recent move to disinvite China from a multinational naval exercise this summer was an "initial response" to the militarization of the islands.
China recently has deployed anti-ship missiles, surface-to-air missiles, electronic jammers and other equipment on the Spratly Islands, and landed a bomber aircraft at Woody Island.
"The placement of these weapons systems is tied directly to military use for the purposes of intimidation and coercion", said Mattis.
US officials also urged worldwide allies to increase its own naval fleet on the territory, as China strengthens its military bases on the Islands of paratsel'.
The U.S., he said, "will continue to pursue a constructive, results-oriented relationship with China, cooperation when possible, and competing vigorously where we must".
"It's clear to me from the conversations I've had, not just the past week but beyond, that China's actions are increasingly alienating many countries because they threaten the ability of countries to determine their own future, to provide for their people", Thornberry said.
South Korea and Japan have expressed concern that Trump may put US security interests ahead of theirs in pursuing a deal with North Korea.
To the ire of Beijing, the US Navy has sailed warships within 12 nautical miles of the Paracel Islands, a contested archipelago off the coast of Vietnam.
Mattis also criticized China's "Belt and Road" initiative without explicitly naming the program, saying that Beijing has to rethink twice if they believe "piling mountainous debts on their neighbors and somehow removing the freedom of political action is the way to engage with them".
China has not sent high-level officials to the Shangri-La conference.
The issue of USA troops in South Korea will not come up in the June 12 summit between Trump and North Korean ruler Kim Jong Un, the American official indicated.
Senior Colonel Zhao Xiaozhuo, a PLA academic, told Mattis that United States freedom of navigation operations, where U.S. naval vessels sail close to Chinese-claimed features, are an "obvious provocation to China's national security and territorial integrity".
"We have seen those who wanted to dominate the region come and go, and we have been with you", Mattis said.
The Pentagon does not comment on future operations but a spokesman, Lieutenant Colonel Christopher Logan, said "we will continue to work with our friends, partners, and allies to ensure a free and open Indo-Pacific".
Mattis said: "We are focussed on modernizing our alliance with both Republic of Korea and Japan, transforming these critical alliances to meet the challenges of the 21st-century".