Acting U.S. Defence Secretary Patrick Shanahan suggested on Saturday that China was responsible for a range of destabilising activities in Asia, stirring already heightened tensions between the world's two largest economies.
In a wide-ranging speech in front of regional defence chiefs at the annual Shangri-La Dialogue in Singapore, Shanahan called on Asian allies to increase their security spending, while emphasising the United States' commitment to the region.
He did not specifically name China when making accusations of "actors" destabilising the region.
"Perhaps the greatest long-term threat to the vital interests of states across this region comes from actors who seek to undermine, rather than uphold, the rules-based international order," Shanahan said in his first major speech since taking over as acting defence secretary in January.
"If the trends in these behaviours continue, artificial features in the global commons could become tollbooths, sovereignty could become the purview of the powerful."
His reference appeared to be to artificial islands built by China in the disputed South China Sea, a strategic waterway claimed almost wholly by Beijing.
While naming China, Shanahan said it was in Beijing's interests to have a constructive relationship with the United States.
But he added: "Behaviour that erodes other nations' sovereignty and sows distrust of China's intentions must end."
"Until it does, we stand against a myopic, narrow, and parochial vision of the future, and we stand for the free and open order that has benefited us all - including China."
Shanahan's comments come as the United States and China are locked in an escalating trade war and at odds over a range of issues from the South China Sea to democratic Taiwan, which China says is part of its sacred territory.
CHINA TO RESPOND
China's Defence Minister Wei Fenghe is due to address Asia's marquee security summit on Sunday when he is expected to criticise the United States over its implied support for a democratic Taiwan.
On Friday, Shanahan held talks with Wei that both sides called "constructive", although their teams later reverted to type with critical comments on each other's defence strategies.
Along with the expected warnings aimed at China, Shanahan referred to cooperation between the two countries in areas like military-to-military exchanges, counter-piracy and joint efforts to reduce the "extraordinary threat" posed by North Korea's military ambitions.
Shanahan also called on U.S. allies to contribute more to their own defences. Burden sharing, from Asia to Europe, has long been a demand of President Donald Trump's administration.
"We need you to invest in ways that take more control over your sovereignty and your own ability to exercise sovereign choices."
