MOSCOW, Russia (AP) — Russia on Thursday sharply raised the stakes in its dispute with the West over Ukraine, with a top diplomat refusing to rule out a Russian military deployment to Cuba and Venezuela if tensions with the United States mount.

Deputy Foreign Minister Sergei Ryabkov, who led the Russian delegation in Monday’s talks with the US in Geneva, said he could “neither confirm nor exclude” the possibility of Russia sending military assets to Cuba and Venezuela if the talks fail and US pressure on Russia mounts.

The Russia-US negotiations in Geneva and a subsequent NATO-Russia meeting failed to narrow the gap on Moscow’s security demands amid a buildup of Russian troops near Ukraine. While Moscow demanded a halt to NATO expansion, Washington and its allies firmly rejected that as a nonstarter.

Speaking in an interview with Russian RTVI TV, Ryabkov noted that “it all depends on the action by our US counterparts”, pointing to Russian President Vladimir Putin’s warning that Moscow could take military-technical measures if the US provokes the Kremlin and turns up military pressure on it.

While voicing concern that NATO could potentially use Ukrainian territory for the deployment of missiles capable of reaching Moscow in just five minutes, Putin has noted that Russian warships armed with the latest Zircon hypersonic cruise missile would give Russia a similar capability if deployed in neutral waters.

Zircon, which Putin said flies at nine times the speed of sound to a range of more than 1,000 kilometres (620 miles), is hard to intercept and could be fitted with conventional or nuclear warheads. It’s set to be commissioned by the Russian navy later this year and installed aboard its frigates and submarines.

Ryabkov’s statement followed his comments last month, comparing the current tensions over Ukraine with the 1962 Cuban Missile Crisis — when the Soviet Union deployed missiles to Cuba and the US imposed a naval blockade of the island. That crisis ended after US President John F Kennedy and Soviet leader Nikita Khrushchev agreed Moscow would withdraw its missiles in exchange for Washington’s pledge not to invade Cuba and the removal of US missiles from Turkey.

Soon after his first election in 2000, Putin ordered the closure of a Soviet-built military surveillance facility in Cuba as he sought to improve ties with Washington. Moscow has intensified contacts with Cuba in recent years as tensions with the US and its allies mounted.

In December 2018, Russia briefly dispatched a pair of its nuclear-capable Tu-160 bombers to Venezuela in a show of support for Venezuelan President Nicolas Maduro amid Western pressure.

Ryabkov said a refusal by the US and its allies to consider the key Russian demand for guarantees against the alliance’s expansion to Ukraine and other ex-Soviet nations makes it hard to discuss such issues as arms control and confidence-building steps that Washington says it’s ready to negotiate.

“The US wants to conduct a dialogue on some elements of the security situation … to ease the tensions and then continue the process of geopolitical and military development of the new territories, coming closer to Moscow,” he said. “We have nowhere to retreat.”

Kremlin spokesman Dmitry Peskov also described this week’s talks as “unsuccessful” even though he noted “some positive elements and nuances.” “The talks were initiated to receive specific answers to concrete principal issues that were raised, and disagreements remained on those principal issues, which is bad,” he said in a conference call with reporters.

Peskov warned of complete rupture in US-Russian relations if proposed sanctions targeting Putin and other top civilian and military leaders are adopted. The measures, proposed by Senate Democrats, would also target leading leading Russian financial institutions if Moscow sends troops into Ukraine.

“It concerns sanctions, which taking into account the inevitable adequate response, effectively amount to an initiative to rupture relations,” he warned, adding that Russia will respond in kind.

Russian Foreign Minister Sergey Lavrov likewise denounced the proposed sanctions as a reflection of US “arrogance”, adding that Moscow expects a written response to its demands from the US and NATO next week in order to mull further steps.

The talks come as an estimated 100,000 Russian troops with tanks and other heavy weapons are massed near Ukraine’s eastern border. Russia has dismissed concerns that it was preparing for an invasion and in turn accused the West of threatening its security by positioning military personnel and equipment in Central and Eastern Europe.

Peskov rebuffed the West’s calls for a Russian troop pullback from areas near Ukraine. “It’s hardly possible for NATO to dictate to us where we should move our armed forces on Russian territory,” he said.

Tensions revolving around Ukraine and Russia’s demands on the West again appeared on the table at Thursday’s meeting of the Organization for Security and Cooperation (OSCE) in Vienna.

Polish Foreign Minister Zbigniew Rau, who assumed the position of the OSCE chairman-in-office, noted in his opening speech that “the risk of war in the OSCE area is now greater than ever before in the last 30 years”.

“For several weeks, we have been faced with the possibility of a major military escalation in Eastern Europe,” he said.

In 2014, Russia annexed Ukraine’s Crimean Peninsula after the ouster of its Moscow-friendly leader and threw its weight behind a separatist insurgency in the country’s east, where over 14,000 people have been killed in more than seven years of fighting.

The tensions over Ukraine also figured high on the agenda of a meeting of European Union foreign ministers in Brest, France. Danish Foreign Minister Jeppe Kofod said it’s important “for Putin to understand that the military threats, the game he’s playing, the way he’s trying to take us back to the darkest days of the Cold War, is totally unacceptable”.

The EU’s foreign policy chief Josep Borrell reiterated that “any further aggression against Ukraine will have massive consequences and severe costs for Russia,” saying that the 27-country bloc is providing 31 million euros ($35.5 million) in logistical assistance to the Ukrainian army and is preparing to send a mission to help the country counter cyber-attacks.