A defiant Vladimir Putin on Wednesday threatened to develop nuclear missiles banned under a treaty with the United States after Washington gave Moscow a deadline to comply with the key arms control agreement.
The latest spike in tensions came a day after US Secretary of State Mike Pompeo said Washington would withdraw from a major Cold War treaty limiting mid-range nuclear arms within 60 days if Russia does not dismantle missiles that the US claims breach the deal.
Putin dismissed Pompeo's statement as a smokescreen, saying Washington had already decided to ditch the Intermediate-Range Nuclear Forces treaty (INF).
"They thought we would not notice," the Kremlin chief said, claiming the Pentagon has already earmarked an amount for the development of missiles banned by the treaty.
"We are against the destruction of this treaty. But if this happens, we will react accordingly."
Putin said about a dozen countries were now producing mid-range missiles of the type banned by the INF treaty.
"Apparently now American partners believe the situation has changed so much that the United States should also have such weapons.
"What will be our answer? A simple one: we will also do this," Putin said.
- 'Head off arms race' -
In Brussels, EU diplomatic chief Federica Mogherini urged Russia and the US to save the treaty, warning that Europe did not want to become a battlefield for global powers once again, as it had been during the Cold War.
"The INF has guaranteed peace and security in European territory for 30 years now," Mogherini said as she arrived for talks with NATO foreign ministers.
In October, President Donald Trump sparked concern globally by declaring the United States would pull out of the deal and build up America's nuclear stockpile "until people come to their senses".
Putin at the time warned that abandoning the treaty and failure to extend another key arms control agreement known as the New START, would unleash a new arms race and put Europe in danger.
On Monday, the US leader said he wants talks with Putin and his Chinese counterpart Xi Jinping "to head off a major and uncontrollable arms race".
Valery Gerasimov, head of Russia's General Staff, said that Moscow would increase the capabilities of its ground-based strategic nuclear arms.
"One of the main destructive factors complicating the international situation is how the US is acting as it attempts to retain its dominant role in the world," he said in comments released by the defence ministry.
"It is for these purposes that Washington and its allies are taking comprehensive, concerted measures to contain Russia and discredit its role in international affairs."
- 'Ballistic missiles' -
Signed in 1987 by then US president Ronald Reagan and Mikhail Gorbachev, the last Soviet leader, the INF resolved a crisis over Soviet nuclear-tipped ballistic missiles targeting Western capitals.
But it was a bilateral treaty between the US and the then Soviet Union, so it puts no restrictions on other major military actors like China.
Pompeo said at a meeting with fellow NATO foreign ministers on Tuesday that there was no reason why the US "should continue to cede this crucial military advantage" to rival powers.
NATO said it was now "up to Russia" to save the treaty.
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 up to 5,500 kilometres (3,400 miles)
The nuclear-capable Russian cruise missiles are mobile and hard to detect and can hit cities in Europe with little or no warning, according to NATO, dramatically changing the security situation on the continent.
US-Russia ties are under deep strain over a number of crises including accusations Moscow meddled in the 2016 US presidential election.
The two Cold War enemies are also at odds over Russian support for Bashar al-Assad's regime in Syria's civil war, and the conflict in Ukraine.
Washington on Tuesday promised Russia more "pain" if Moscow did not release three Ukrainian vessels and 24 sailors captured off Crimea last last month.