The US government on Friday pledged "massive consequences" against Moscow if an upcoming bilateral security dialogue fails to prevent any further build-up by Russia's military on the border with Ukraine.
The massing of troops and military equipment along the Russian side of Ukraine's Donbass region border will be a key topic during talks next week between US President Joe Biden and Russian leader Vladimir Putin, and will include two working groups established as part of the "strategic stability dialogue".
"It'll be very difficult to make actual progress if Russia continues to escalate its military build-up and its inflammatory rhetoric," US Secretary of State Antony Blinken told reporters in Washington.
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"And we've been clear with Russia about what it will face if it continues on its path, including economic measures that we haven't used before. Massive consequences," he said.
Administration officials have not offered any details about what such a sanctions package would look like. But a senior State Department official speaking to reporters later on Friday described them as "an order of magnitude more serious than anything we've done before", and said the US was "unified" with allies about moving ahead with the punitive measures should Russia engage in further aggression.
Biden and Putin agreed to resume the strategic security dialogue when they met in Switzerland in June, which followed the US leader's intensive efforts to bolster ties with Nato, the EU and the Group of Seven industrialised nations.
Administration officials warned on Friday of a misinformation campaign by Moscow whereby, after the talks, Russian officials would make public comments that did not reflect the substance of the negotiations, with the senior State Department official urging US allies "to view those comments with extreme scepticism".
Part of Moscow's strategy in talks, said Blinken, was "to put out a list of absolutely non-starter demands, and then to claim that the other side is not engaging, and then to use that as somehow justification for aggressive action".
Biden tells Ukraine leader US will 'respond decisively' if Russia invades
Those demands include the rescission of a 2008 Nato commitment to Ukraine that the country would one day become a member of the defence alliance and a declaration that Nato would not deploy weapons in countries bordering Russia that could threaten Moscow's security.