President Donald Trump told reporters Monday that the United States would increase its nuclear arsenal until other nations “come to their senses,” threatening an arms race days after he said he would withdraw the US from a Cold War nuclear treaty.

Trump announced over the weekend that he intended to pull the US out of the Intermediate-Range Nuclear Forces Treaty (INF) with Russia and accused Moscow of violating the deal.

The signing of the treaty in 1987 was seen as a watershed moment during the end days of the Cold War, helping to eliminate thousands of land-based missiles with ranges between approximately 300 and 3,400 miles.

Trump repeated on Monday that Russia had not adhered to the treaty and said his vow to increase the US nuclear stockpile included a posture against China as well.

“Until people come to their senses, we will build it up,” Trump said to reporters outside the White House.

“It’s a threat to whoever you want,” Trump said. “And it includes China, and it includes Russia, and it includes anybody else that wants to play that game. You can’t do that. You can’t play that game on me.”

Trump noted that China was not a party to the agreement, but said, “They should be included.”

His threat to increase the US nuclear arsenal prompted international concern. “The US does not need further expansion of its nuclear capabilities. Neither does Russia. They can annihilate each other many times over,” said associate professor Marianne Hanson, a nuclear arms control expert from the University of Queensland.

“Instead of winding up the rhetoric and threatening retaliatory measures, both Moscow and Washington need to engage in diplomacy and confidence building measures, together with a gradual phased, balanced and monitored reduction in their weapons,” she added.

Chinese Foreign Ministry spokesperson Hua Chunying told reporters Monday that it was “wrong” for the US to cite China as a reason to pull out of the treaty, which he said was important for “maintaining global strategic balance and stability.”

“Withdrawing unilaterally from the treaty will have a multilateral impact,” Hua said.

Russia has denied it is in violation of the treaty, and said it would be forced “to take measures” if Washington began developing new missile systems. President Vladimir Putin plans to discuss the decision with US national security adviser John Bolton, who he is due to meet on Tuesday in Moscow, Russia’s state-run news agency, RIA Novosti, reported.

Some analysts see the Trump administration’s aversion to international agreements and the views of Bolton as a driving force behind the decision. In 2011, Bolton wrote an opinion piece outlining why the US should leave the treaty.

Former Soviet leader Mikhail Gorbachev — who signed the deal with US President Ronald Reagan — said the US announcement was “very irresponsible.”

Fears of new nuclear arms race

The European Union warned Trump pulling out of the treaty would risk a new nuclear arms race and urged the US and Russia to “remain engaged in constructive dialogue.”

“The INF contributed to the end of the cold war and constitutes a pillar of European security architecture since it entered into force 30 years ago,” a spokeswoman for the EU foreign policy chief, Federica Mogherini, said in a statement.

“Thanks to the INF treaty, almost 3,000 missiles with nuclear and conventional warheads have been removed and verifiably destroyed,” the statement said. “The world doesn’t need a new arms race that would benefit no one and on the contrary would bring even more instability.”

NATO Secretary General Jens Stoltenberg said earlier this month that the military alliance remained “concerned about Russia’s lack of respect for its international commitments, including the Intermediate-Range Nuclear Forces Treaty, the INF Treaty.”

He continued, “After years of denials, Russia recently acknowledged the existence of a new missile system, called 9M729. Russia has not provided any credible answers on this new missile. All allies agree that the most plausible assessment would be that Russia is in violation of the treaty. It is therefore urgent that Russia addresses these concerns in a substantial and transparent manner.”

Wider repercussions

Some observers said Trump’s announcement could be a move to push Russia and China into compliance, but others suggest both countries may have something to gain by ditching the agreement.

Withdrawing from the treaty would allow the US to develop a missile similar to the one that Russia has tested. Conversely, the announcement could also allow Russia to blame Washington for the treaty’s demise, while pursuing an arsenal of nuclear missiles more freely.

Mark Bell, an assistant professor of political science at the University of Minnesota, said that if Washington withdraws from the treaty, the move could affect Europe and US-China ties more than US-Russia relations.

“The INF is something that matters more to US allies in Europe than it does to the US, since they are the ones in range of INF weapons,” Bell told CNN. “US withdrawal therefore has the potential to exacerbate current US-EU tensions.”

He added that some in the US defense community would like Washington to have the option of deploying land-based cruise missiles in Asia in the future. “Leaving the INF would allow the US to do this,” he said.

Bell doubted that a withdrawal from the treaty would cause a serious rupture of the current strategic balance.

“This move has the potential to somewhat destabilize the current strategic balance in Europe,” he said. “Though I would be surprised if it led to a major arms race: I suspect both the US and Russians will continue to do more or less what they are currently doing.”

Former State Department spokesman Rear Adm. John Kirby, a CNN military and diplomatic analyst, previously said: “I do think, if we pull out, we really do need to think about how we are going to, right now because we don’t have the same capability as the Russians have with this particular missile. How are we going to try and counter that? How are we going to try and help deter use of it on the continent of Europe?”

Despite threatening to spend vast sums to increase the US nuclear arsenal, on Monday Trump said ultimately he hoped to bring the US back onto the path of reducing its weapons stockpiles.

“We have more money than anybody else by far,” Trump said. “We’ll build it up until they come to their senses. When they do, then we’ll all be smart, and we’ll all stop. And by the way not only stop, we’ll reduce, which I would love to do. But right now, they (Russia) have not adhered to the agreement.”