Deputy Foreign Minister Sergei Ryabkov, who led the Russian delegation in Monday's talks with the United States in Geneva, said in televised remarks that he would neither confirm nor exclude the possibility that Russia could send military assets to Cuba and Venezuela.

The negotiations in Switzerland and Wednesday's NATO-Russia meeting in Austria failed to narrow the gap on Russian security demands amid a build-up of its troops near Ukraine.

While Russia demanded a halt to NATO expansion, the US and its allies firmly rejected them as a non-starter.

Speaking in an interview with Russian RTVI TV, Ryabkov noted that "it all depends on the action by our US counterparts," adding that President Vladimir Putin has warned that Russia could take military-technical measures if the US provokes the country and turns up military pressure on it.

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 countries raises doubts about continuing the talks.

Kremlin spokesman Dmitry Peskov noted "some positive elements and nuances" during the talks but described them as "unsuccessful" because of stark disagreements on Russia's key demands.

"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 a complete rupture in US-Russian relations if proposed sanctions targeting Putin and other top civilian and military leaders are adopted.

The measures, proposed by US Senate Democrats, would also target leading leading Russian financial institutions if Russia sends troops into Ukraine.

Peskov criticised the proposals as an attempt to up the pressure on Russia during the talks, saying it wouldn't work.

"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 to protect its interests.

The talks come as an estimated 100,000 combat-ready Russian troops, tanks and heavy military equipment are massed near Ukraine's eastern border.

The build-up has caused deep concerns in Kyiv and its allies that Russia is preparing for an invasion.

Russia denies that it is pondering an invasion and in turn accuses NATO of threatening its security by positioning military personnel and equipment in central and eastern Europe.

Peskov rebuffed NATO's calls for Russia to help de-escalate tensions by pulling back troops from areas near Ukraine, noting that the country is free to move them wherever it deems necessary on its own territory.

"It's hardly possible for NATO to dictate to us where we should move our armed forces on the Russian territory," he said.

Peskov underscored that Russia is ready to continue the talks but wants them to produce results.

"There will be no deficit of a political will to continue the negotiations," he said.

Australian Associated Press