The United States and its European allies appeared no closer to resolving a crisis with Russia over a possible renewed war in Ukraine, as Western officials flatly rejected Moscow’s call to pledge there would be no further eastward expansion of NATO, while a top Russian negotiator said diplomacy already had reached a “dead end.”

The impasse came after three rounds of high-stakes talks this week in Geneva, Brussels and Vienna, where the United States hoped to placate Russia by proposing reciprocal restraints on missile placements and military exercises in Europe. The Russian delegation expressed interest in those areas but still accused Washington and its allies of stonewalling on the Kremlin’s core demands.

This week’s flurry of meetings was seen as a critical bid to defuse a crisis amid fears that Russia — which has amassed more than 100,000 forces near its western border — could once again invade Ukraine, the neighboring nation where Russia has been fueling a separatist conflict for nearly eight years.

Ukraine is seeking NATO membership and deepening military and economic ties with the West, but the country is seen by Moscow as part of its sphere of influence, with Russian President Vladimir Putin last year asserting that “true sovereignty of Ukraine is possible only in partnership with Russia.”

Massing troops near Ukraine as leverage, Putin has demanded sweeping security guarantees from the United States and NATO, including a halt to any NATO expansion, a rollback of the alliance’s infrastructure and weaponry to its 1997 boundaries — which would remove any military presence in Poland and the Baltic States, among other countries — and a ban on offensive strike weapons near Russia’s borders.

The Russian stance would fundamentally reshape European security and reflects Putin’s attempt to rework the fallout of the collapse of the Soviet Union, which left Russia weakened as NATO expanded. U.S. officials have called his demands regarding NATO non-starters.

In a rapid-fire series of statements from Kremlin and Foreign Ministry officials on Thursday, Russia gave a categoric thumbs down to the Western effort this week to ease tensions.

In quick succession, Kremlin spokesman Dmitry Peskov, Foreign Minister Sergei Lavrov and Alexander Lukashevich, Russia’s ambassador to the Organization for Security and Cooperation in Europe (OSCE), all condemned the refusal of the United States and NATO to accept Russia’s demands.

Deputy Foreign Minister Sergei Ryabkov said Thursday there were “no grounds” to continue the security talks — a rebuff to the West that amped up the pressure on the Biden administration and sent the ruble and the Russian stock market tumbling amid fears of a renewed war.

Ryabkov said the United States and its allies have rejected Moscow’s key demands and have offered to negotiate only on topics of secondary interest to Russia.

“There is, to a certain extent, a dead end or a difference in approaches,” he said in a Russian television interview. Without some sign of flexibility from the United States, he said, “I do not see reasons to sit down in the coming days, to gather again and start these same discussions.”

White House national security adviser Jake Sullivan, in a briefing Thursday, said top Russian officials “over the course of the week have given both hopeful signs and deeply pessimistic signs,” and noted that the United States remained prepared for any contingency.

If the Kremlin proceeds with an invasion, Sullivan said, Russia would face significant financial sanctions and export controls targeting its strategic industries, and Washington would “dramatically ramp up” military aid to Ukraine in addition to bolstering its NATO allies with new forces and materiel — all contrary to what Putin wants.

Sullivan also warned that Russia is laying the groundwork for sabotage and information operations to fabricate a false pretext for invading Ukraine, and said the U.S. government would release more information about those activities in the next 24 hours.

His comments came after the OSCE convened its permanent council in Vienna, where the head of the American delegation, U.S. Ambassador Michael Carpenter, called on member states to “decisively reject blackmail and never allow aggression and threats to be rewarded.”

In a briefing after the Vienna meeting, Carpenter said he expected follow-on talks in the coming weeks about European security under the OSCE, but noted that “the drumbeat of war is sounding rather loud and the rhetoric is rather shrill.” He said the United States would be happy to discuss transparency about military exercises and other matters but wouldn’t be budging on sacrosanct principles that underpin the international system.

“We’re not going to entertain spheres of influence. We’re not going to restrict sovereign states’ rights to choose their alliances. And we’re not going to privilege one state’s security over that of another,” Carpenter said.

The final decision on any further dialogue with the West — and whether the crisis leads to a renewed war — rests with Putin.

Lavrov, who described the Western position as “arrogant, unyielding and uncompromising,” said Thursday that Putin would decide on further action after receiving written responses to Moscow’s demands next week. It wasn’t immediately clear, however, if U.S. officials were preparing a written response to the two draft treaties Russia made public last month.

Putin has threatened to take unspecified “military-technical” measures if NATO does not accede to his demands.

U.S. officials have countered that it is Russia that has invaded two neighboring nations — Ukraine and Georgia — and annexed Crimea from Ukraine, as well as using chemical weapons in attempted assassinations in Europe, posing a threat to the continent.

Throughout the talks this week, Russian officials denied plans to attack Ukraine and rebuffed NATO calls to de-escalate, saying Russia has a right to move troops and forces on its own territory.

U.S. intelligence analysis has found that the Russian military is preparing for a multipronged offensive against Ukraine that could include as many as 175,000 forces and take place this winter.

In his television interview, Ryabkov also refused to rule out sending Russian military infrastructure to Cuba or Venezuela if tensions with Washington continued to rise.

In addition to calling the talks unsuccessful, Peskov, the Kremlin spokesman, on Thursday highlighted a bill announced the day before by Democratic senators for tough new sanctions against Russians, including Putin, if there is military action against Ukraine.

Peskov called it “extremely negative.” Sanctioning a head of state, he said, “is an outrageous measure that is comparable to breaking off relations.”

Dixon reported from Belgrade, Serbia. Missy Ryan in Washington contributed to this report.

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