Beijing (AFP) – China warned Tuesday it would take unspecified countermeasures if the United States goes ahead with plans to deploy ground-based missiles in the Asia-Pacific region.

The comments come days after US Defense Secretary Mark Esper said the US was now free to deploy the weapons following its withdrawal last week from the Intermediate-Range Nuclear Forces (INF) treaty with Russia.

“China will not stand idly by and will be forced to take countermeasures should the US deploy intermediate-range ground-based missiles in this part of the world,” said Fu Cong, the director of arms control at the Chinese foreign ministry.

“And we also call on our neighbours, our neighbouring countries, to exercise prudence and not to allow a US deployment of its intermediate-range missiles on (their) territory,” he added, naming Australia, Japan and South Korea.

“That would not serve the national security interest of these countries,” he said.

Australia on Monday ruled out the possibility of the missiles being deployed on its soil, saying Canberra had not even been asked to host them.

The INF treaty was considered a cornerstone of the global arms control architecture but the United States said the bilateral pact had given other countries — namely China — free rein to develop their own long-range missiles.

Esper, the new Pentagon chief, said Saturday that Washington would like to deploy the missiles “sooner rather than later,” speaking to reporters on a plane to Sydney at the start of a week-long tour of Asia.

“I would prefer months… But these things tend to take longer than you expect.”

The announcement was the latest US plan to irk China, which is vying with Washington for influence in the region, but Esper said Beijing should not be surprised.

The rise of a militarily more assertive China in the region has worried traditional US allies such as Australia and New Zealand, and Beijing’s actions in the South China Sea have alarmed neighbours with competing territorial claims to the strategic waterway.

Esper did not specify where the US intended to deploy the weapons but experts say the most likely location for deployment is the island of Guam, which hosts significant US military facilities.

Washington withdrew from the INF treaty on Friday after accusing Russia of violating it for years.

Under the pact signed in 1987 by then US president Ronald Reagan and Soviet leader Mikhail Gorbachev, Washington and Moscow agreed to limit the use of conventional and nuclear missiles with a range of 500-5,000 kilometres (300-3,000 miles).

But its unravelling had been on the cards for months amid worsening ties between Russia and the US.