U.S. national security adviser John Bolton on Tuesday linked the deployment of intermediate-range ballistic missiles (IRBMs) in Asia to protecting America’s allies in the region — including Japan — despite Chinese warnings it would take retaliatory countermeasures.

Bolton said that any U.S. deployment of the missiles would be a defensive move as China continues to amass a large arsenal of weapons that put American and Japanese military bases and facilities within striking distance.

“We’re talking only about defending our deployed forces, our allies in South Korea, Japan and elsewhere,” Bolton said in an interview with Fox News. “It’s China that’s built up its military forces and posed a threat.”

His comments came as the new U.S. defense chief, Mark Esper, said en route to Japan on Tuesday that he isn’t currently asking allies in Asia, including Japan, to host American missiles on their territory.

Esper made the comments during a tour of the Asia-Pacific that includes stops in Australia, Japan and South Korea — three countries Beijing has warned against hosting the missiles.

“I have never asked anybody about the deployment of missiles in Asia,” Esper said, according to a transcript provided by the Pentagon. “We are quite some ways away from that. It’s going to take, again, a few years to actually have some type of initial operational-capable missiles, whether they are ballistic, cruise — you name it, to be able to deploy.”

Esper appeared to tone down remarks over the weekend in which he said that Washington is hoping to deploy new ground-based IRBMs to Asia “sooner rather than later” — possibly within months. Such a move would have huge ramifications for regional security.

The defense chief did not say where the missiles could be based, but experts have said Japan, South Korea and Australia, as well as the U.S. territory of Guam, were among possible deployment sites.

China on Tuesday warned that any country accepting the deployment of the weapons would face retaliation.

“China will not stand idly by and be forced to take countermeasures should the U.S. deploy intermediate-range ground-based missiles to this part of the world,” said Fu Cong, director of the Foreign Ministry’s Arms Control Department.

He also advised other nations, particularly Japan, South Korea and Australia, to “exercise prudence” and not allow the U.S. to deploy such weapons on their territory, saying that would “not serve the national security interests of these countries.”

In an editorial published Sunday, the state-run Global Times newspaper, a hawkish tabloid, also warned against such a move by Japan or South Korea, saying that it would trigger an arms race and “geopolitical chaos.”

“Japan and South Korea must remain sober,” it said. “Their interests have been diverse due to Asia’s vigorous development. The U.S. is no longer their only source of benefits. The two countries’ relations with both China and Russia have stayed largely smooth and economic cooperation is expanding. It will be their nightmare if they follow the U.S. to start a new Cold War.”

The editorial also warned that deploying the missiles would lead to increasingly closer ties between Beijing and Moscow.

“It is believed that China and Russia will strengthen strategic coordination and join hands to resist the U.S. plan,” it said. “It is hoped that Japan and South Korea will not turn themselves to cannon-fodder in the aggressive U.S. Asian policy.”

On Wedneday, Esper warned of the threat China poses to the region during talks in Tokyo, accusing it of “militarization of the global commons” as well as economic coercion, intellectual property theft and environmental devastation. “This behavior destabilizes our region,” he said at a meeting with his Japanese counterpart, Takeshi Iwaya.

The U.S. defense chief told Iwaya he wanted to discuss capabilities the two countries’ alliance needed to deter and respond to regional threats.

Washington has pinned much of the blame for its exit last week from the Intermediate Range Nuclear Forces Treaty on Russian violations of the landmark pact, but a closer look shows that China’s buildup of its missile forces also played a large part in the decision to abrogate the decades-old arms-control deal.

The 1987 treaty between Washington and Moscow banned all land-based missiles with ranges of 500 to 5,500 km (310 to 3,420 miles). The pact covered short- and intermediate-range missiles that can carry both nuclear and conventional warheads, but did not ban air- or sea-launched weapons.

American officials have said that any future deployment of missiles to Asia would be purely conventional and not nuclear capable.

The U.S. estimates that approximately 95 percent of the missiles in the People’s Liberation Army Rocket Force arsenal fall in the 500 to 5,500-km range — meaning key U.S. facilities throughout Japan could already be within range of thousands of difficult-to-defeat advanced ballistic and cruise missiles.

In his interview, Bolton said that China, which was not part of the INF Treaty, had been “free to do what they wanted” in terms of missile development.

“That’s one reason President Trump withdrew from the treaty,” he said, adding that China currently has “thousands of such missiles deployed.”

Still, both Australia and South Korea have frowned on the prospect of hosting the U.S. weapons — and effectively turning their countries into targets for Chinese missiles.

On Monday, Australian Prime Minister Scott Morrison said U.S. IRBMs will not be deployed in Australia, though the two allies did pledge to strengthen opposition to Chinese activities in the Asia-Pacific region.

“It’s not been asked to us, not being considered, not been put to us,” Morrison said. “I think I can rule a line under that.”

South Korea’s Defense Ministry also said Monday that it has had no official discussions with the U.S. on the matter and has not reviewed the issue internally, though it has plans to do so, the Yonhap news agency reported.

On Sunday, U.S. Secretary of State Mike Pompeo said that Washington will continue to assess the plans for deployment.

“We will evaluate whether there are certain systems, certain missile systems that make sense to put in certain countries,” Pompeo said in an interview with Sky News. “These will be long, consultative processes as we work our way through them. But we’ll never hesitate, if we think it’s in the strategic interest of the United States of America and the strategic interest of an ally, to engage in a deployment, an operation for freedom of navigation or the deployment of certain systems.”

Information from Bloomberg added