U.S. Secretary of State Antony Blinken met his Russian counterpart on Thursday to warn him face-to-face of the "serious consequences" Russia would suffer if it invaded Ukraine and to urge him to seek a diplomatic exit from the crisis.
Blinken delivered the warning to Russian Foreign Minister Sergey Lavrov at a meeting in Stockholm, a day after declaring that Washington was ready to respond resolutely, including with hard-hitting sanctions, in the event of a Russian attack.
"The best way to avert the crisis is through diplomacy," Blinken told reporters before going into talks with Lavrov at a moment of acute East-West tensions over Ukraine.
He said Moscow and Kyiv should each fulfil their obligations under the 2014 Minsk peace process, which was designed to end a war between pro-Russian separatists and Ukrainian government forces in the east of the former Soviet republic.
Washington was willing to facilitate this, Blinken said, but "if Russia decides to pursue confrontation, there will be serious consequences."
Lavrov told reporters Moscow was ready for dialogue with Kyiv. "We, as President (Vladimir) Putin has stated, do not want any conflicts," he said.
The two men talked for about 30 minutes on the fringes of a meeting of the Organization for Security and Co-operation in Europe (OSCE) in Stockholm, in the highest-level contact between the two sides since a summit between Putin and U.S. President Joe Biden in June.
"Should Moscow choose the path of military escalation, the Secretary (Blinken) made clear that the United States and our allies are prepared to impose significant costs," State Department spokesperson Ned Price said.
A senior State Department official said Blinken and Lavrov had a "serious, sober and business-like" meeting.
The official said there had been a constructive exchange on implementing the existing Minsk peace agreements for eastern Ukraine as a possible pathway out of the crisis, and further intense diplomacy was likely in coming days.
Ukraine says Russia has amassed more than 90,000 troops near their long shared border, while Moscow accuses Kyiv of pursuing its own military build-up. It has dismissed as inflammatory suggestions it is preparing for an attack on Ukraine and has defended its right to deploy troops on its own territory as it sees fit.
The Kremlin said on Thursday that the probability of a new conflict in eastern Ukraine remained high and that Moscow was concerned by "aggressive" rhetoric from Kyiv and an increase in what it called provocative actions along the line of contact between government forces and the pro-Russian separatists.
Kyiv has denied any intention of trying to take back the rebel regions by force, accusing Russia of spouting "propaganda nonsense" in order to provide cover for its own aggressive intentions.
Russia said separately it had arrested three suspected Ukrainian intelligence agents, including one accused of planning to carry out an attack using two homemade bombs, allegations that Kyiv dismissed as trumped up.
Last week Ukraine's president said Kyiv had thwarted a Russian-backed coup plot, which the Kremlin denied.
East-West relations have sunk to their lowest level since the Cold War and the demise of the USSR, a point accidentally underlined by U.S. Defense Secretary Lloyd Austin when he said during a visit to South Korea: "The best case... is that we won't see an incursion by the Soviet Union into the Ukraine."
Ukraine's tilt towards the West since ousting a pro-Russian president in 2014 has enraged Moscow, which says it will not accept NATO membership for Ukraine or the stationing of NATO missiles there that could threaten it.
Putin said this week that Russia was ready with a newly tested hypersonic weapon of its own if the West deployed missiles in Ukraine that could hit Moscow within a few minutes.
In his speech to the OSCE earlier on Thursday, Lavrov said military tensions were rising on the continent and he hoped that Russia's proposals on a new European security pact would be carefully considered.
"The architecture of strategic stability is rapidly being destroyed, NATO refuses to constructively examine our proposals to de-escalate tensions and avoid dangerous incidents," Lavrov said.
"On the contrary, the alliance's military infrastructure is drawing closer to Russia's borders. The nightmare scenario of military confrontation is returning."