The Kremlin said on Monday that Washington's withdrawal from a key Cold War-era nuclear treaty would make the world more dangerous, as Donald Trump's national security advisor met senior Russian officials in Moscow.
John Bolton is expected to discuss Trump's plan to jettison the three-decade-old Intermediate-Range Nuclear Forces Treaty with Russian President Vladimir Putin on Tuesday.
On Monday, Bolton discussed the fate of the treaty with Russian Security Council Chief Nikolai Patrushev and was expected to meet with Foreign Minister Sergei Lavrov later in the day.
Putin's spokesman Dmitry Peskov told journalists that ditching the treaty "will make the world more dangerous" and rejected US claims that Moscow has violated the pact, instead accusing Washington of doing so.
"It is the United States that is eroding the foundations and main elements of this pact" with its missile defense capabilities and drones, he said.
Lavrov said he was waiting to hear Bolton's "official explanation" regarding Trump's intentions, adding that for the moment the US side has not initiated the official procedure for exiting the treaty.
Trump on Saturday claimed that Russia had long violated the treaty, known as the INF.
"We're the ones who have stayed in the agreement and we've honoured the agreement, but Russia has not unfortunately honoured the agreement, so we're going to terminate the agreement and we're going to pull out," he told reporters.
"Russia has violated the agreement. They've been violating it for many years," he said.
"And we're not going to let them violate a nuclear agreement and go out and do weapons (while) we're not allowed to."
EU, China concerned
Trump's announcement raised global concerns, with the European Commission urging the US and Russia to pursue talks to preserve the treaty and China calling on Washington to "think twice".
The Commission, the 28-nation European Union executive, stressed that the INF has been a mainstay of European defence for the last three decades.
"The US and the Russian Federation need to remain in a constructive dialogue to preserve this treaty and ensure it is fully and verifiably implemented," spokeswoman Maja Kocijancic told reporters.
She said the agreement was important for both European and global security.
Chinese foreign ministry spokeswoman Hua Chunying said a unilateral withdrawal from the treaty "will have a multitude of negative effects."
Trump argued that the treaty does nothing to hold non-signatory China back from developing missiles, but Hua said that "it is completely wrong to bring up China when talking about withdrawal from the treaty".
The treaty banning intermediate-range nuclear and conventional missiles was signed in 1987 by then US president Ronald Reagan and Mikhail Gorbachev, the last Soviet leader.
Gorbachev on Sunday said that "dropping these agreements... shows a lack of wisdom" and was a "mistake".
The INF resolved a crisis over Soviet nuclear-tipped ballistic missiles targeting Western capitals.
Arms race fears
The latest row between Russia and the United States comes ahead of what is expected to be a second summit between Trump and Putin this year.
Analysts have warned that the latest rift could have lamentable consequences and drag Russia into a new arms race.
The Trump administration has complained of Moscow's deployment of Novator 9M729 missiles, which Washington says fall under the treaty's ban on missiles that can travel distances of between 310 and 3,400 miles (500 and 5,500 kilometres).
Britain's The Guardian newspaper said that Bolton himself is pressuring Trump to leave the INF and had blocked talks to extend the New Start treaty on strategic missiles set to expire in 2021.
US-Russia ties are under deep strain over accusations Moscow meddled in the 2016 US presidential election. The two countries are also at odds over Russian support for the Syrian government in the country's civil war, and the conflict in Ukraine.
On Friday, the US Justice Department indicted the finance chief of Russia's leading internet troll farm for allegedly interfering with US congressional elections to be held in November.
Russia accused the United States of fabricating the charges.
Putin and Trump will both be in Paris on November 11 to attend commemorations marking 100 years since the end of World War I.