Both Beijing and Moscow expressed their regret at the lapse of the last Russia-US nuclear arms control treaty.

The Kremlin says Russia will continue to be a responsible nuclear power, despite the expiry of the last nuclear arms control treaty between Moscow and Washington, which experts say risks ushering in a new global arms race.

The New START treaty expires on Thursday, marking the end of more than half a century of limits on the United States and Russia’s strategic nuclear weapons.

“Today the day will end, and it [the treaty] will cease to have any effect,” Kremlin spokesperson Dmitry Peskov told reporters on Thursday. Arms control experts had previously said their assumption was that it expired at the end of Wednesday.

Russia had suggested both sides voluntarily extend the terms of the agreement for one year to provide time to discuss a successor treaty, a proposal which it said US President Donald Trump had never formally answered.

“The agreement is coming to an end. We view this negatively and express our regret,” said Peskov, who said the matter had come up in a call between Russian President Vladimir Putin and Chinese President Xi Jinping a day earlier.

“What happens next depends on how events unfold. In any case, the Russian Federation will maintain its responsible and attentive approach to the issue of strategic stability in the field of nuclear weapons and, of course, as always, will be guided first and foremost by its national interests.”

New START, first signed in Prague in 2010 by then presidents Barack Obama and Dmitry Medvedev, limited each side’s nuclear arsenal to 1,550 deployed strategic warheads – a reduction of nearly 30 percent from the previous limit set in 2002.

Deployed weapons or warheads are those in active service and available for rapid use as opposed to those in storage or awaiting dismantlement.

It also allowed each side to conduct on-site inspections of the other’s nuclear arsenal, although these were suspended during the COVID-19 pandemic and have not resumed since.

‘China will not participate in disarmament negotiations’

China’s Ministry of Foreign Affairs joined a growing international chorus expressing regret over the treaty’s expiry.

“China regrets the expiration of the New START treaty, as the treaty is of great significance to maintaining global strategic stability,” Chinese Foreign Ministry spokesperson Lin Jian said on Thursday.

“The international community is generally concerned that the expiration of the treaty will have a negative impact on the international nuclear arms control system and the global nuclear order.”

Trump has said he wants a better deal that will also bring in China. But Beijing refuses to negotiate with the other two countries because it has only a fraction of their warhead numbers – an estimated 600, compared with about 4,000 each for Russia and the US.

Lin reiterated this point, adding that China would not be joining the bilateral arms‑reduction talks.

“China’s nuclear forces are not on the same level as those of the United States and Russia, and China will not participate in disarmament negotiations at this stage,” Lin said.

Russia and the US together control more than 80 percent of the world’s nuclear warheads.

China’s nuclear arsenal, however, is growing faster than any country’s, by about 100 new warheads a year since 2023, according to the Stockholm International Peace Research Institute (SIPRI).

China is estimated to have at least 600 nuclear warheads, SIPRI says – well below the 800 each at which Russia and the US were capped under New START.

The White House said this week that Trump would decide the way forward on nuclear arms control, which he would “clarify on his own timeline”.

A NATO official, speaking on condition of anonymity, called on the US and Russia to act with “responsibility and restraint” to maintain “global security”.

The official added that Russia and China were both ramping up their nuclear capabilities and that NATO “will continue to take steps necessary” to ensure its own defences.