Vladimir Putin warned Russia was prepared to take “military measures” in response to “aggressive” Western actions in Ukraine, hinting at potential conflict.
Speaking at a defence ministry meeting, the Russia president vowed to “react toughly to unfriendly steps”, accusing the United States and Nato of stoking tensions near Moscow’s borders.
For weeks the Kremlin has warned of potential action against western encroachment towards its frontiers, but this was the first time Mr Putin has publicly intervened.
“We are concerned about the build-up of the US and Nato military forces directly near the Russian borders, as well as the conduct of large-scale exercises, including unplanned ones.” Mr Putin said.
He told Russian defence ministry officials on Tuesday that if the West continued its “obviously aggressive stance” then Moscow would have no choice but to hit back with “appropriate retaliatory military-technical measures”.
His intervention comes amid growing panic that Russia is prepared to launch a large-scale attack on its former-Soviet neighbour Ukraine.
The United States and Nato allies have accused Moscow of amassing more than 100,000 troops near its border with eastern Ukraine, where Kiev has been battling Russian separatists since 2014.
Russia denies plotting an invasion and has demanded that the transatlantic military alliance end membership talks with Ukraine and that its forces be withdrawn from ex-Soviet states.
Mr Putin said he was “extremely concerned” over what he described as US cruise missile deployments in Poland and Romania.
“If this infrastructure moves further – if US and Nato missile systems appear in Ukraine – then their approach time to Moscow will be reduced to seven or 10 minutes,” he said.
Despite the threat of conflict, the Russian president said that Moscow’s demands were not an “ultimatum.”
“Russia is against bloodshed, it wants to resolve issues by political and diplomatic means, but with security guarantees,” he said.
Speaking at the same meeting, Sergey Shoygu, Russia’s defence minister, accused American private companies of “preparing a provocation with chemical components in Eastern Ukraine”.
He also said the US had deployed about 8,000 troops in Eastern Europe.
The US is expected to start talks with Russia next year over its security demands in a bid to find a diplomatic solution to ease the tensions.
Karen Donfried, US assistant secretary of state, said: “We are prepared to discuss those proposals that Russia put on the table. There are some things that we are prepared to work on, and that we do believe there is merit in having a discussion.”
Nato has signalled it is also prepared to open talks. The North Atlantic Council, the alliance’s decision-making body, said last week it was “ready for meaningful dialogue with Russia… on the basis of reciprocity”.
Western diplomats have warned against allowing Russia to set the rules of engagement in any discussions.
Andrea Sasse, a spokeswoman for the German foreign ministry, said: “We will discuss these proposals that are currently on the table . . . with all our partners in the EU and in Nato.
“It is important that in our dialogue that we have [with Russia] at the moment, we remain true to our own principles. And one of them is the indivisibility of the security of all Nato member states. And that has consequences for what we can and can’t accept.”
But instead of withdrawing from Russia’s borders, the UK and US have dispatched cybersecurity experts to Ukraine over fears of a Kremlin-led cyberattack on the country’s power grid.
The Telegraph understands British military cyber specialists have been sent to help bolster the country’s defences, given the cyber attacks the country has experienced in the past which have been attributed to Russia.
The specialists are likely to have come from the National Cyber Force, a mix of personnel from the armed forces, GCHQ and MI6, although their mission was not thought to include targeting Russian systems.
A government spokesperson said: “The UK and our allies are providing a range of support to Ukraine, but this support is fundamentally defensive in nature.”
Russian hackers are said to have easy access to the network because it was built when Ukraine was still a member of the Soviet Union and connected to Moscow.
“There’s too much to patch,” one American official told the New York Times, suggesting the lack of a quick-fix for the system.
Sources told the publication they are on high-alert for a repeat of the December 2015 hack on Ukraine’s power grid, which resulted in power outages for 230,000 consumers.