Russia has warned it would quickly take "retaliatory measures" if the US and its allies reject its security demands over Nato and Ukraine, raising pressure on the West amid concerns that Moscow is planning to invade its neighbour.
The Kremlin has repeatedly denied it has any such designs, but the US and its Nato allies are worried about Russia deploying an estimated 100,000 troops near Ukraine and launching a series of sweeping military manoeuvres.
As part of the drills, motorised infantry and artillery units in southwestern Russia practised firing live ammunition, warplanes in Kaliningrad on the Baltic Sea performed bombing runs, dozens of warships sailed for training exercises in the Black Sea and the Arctic, and Russian fighter jets and paratroopers arrived in Belarus for joint war games.
At stake is the future of Ukraine: Russia has demanded guarantees that Nato will never admit the country and other ex-Soviet nations as members and that the alliance will roll back troop deployments in other former Soviet bloc nations.
Some of these, like the membership pledge, are nonstarters for Nato, creating a seemingly intractable stalemate that many fear can only end in a war.
Speaking to lawmakers, Russian Foreign Minister Sergey Lavrov said he and other top officials will advise President Vladimir Putin on the next steps after receiving written replies from the United States to the demands.
Those answers are expected this week — even though the US and its allies have already made clear they will reject Russia's top demands.
"If the West continues its aggressive course, Moscow will take the necessary retaliatory measures," Lavrov said.
But he indicated Russia wouldn't wait forever. "We won't allow our proposals to be drowned in endless discussions," he said.
He mocked fears of an imminent invasion, saying that "our Western colleagues have driven themselves up into a militarist frenzy", adding sardonically that "the Ukrainian elite itself has grown a bit scared by the Western scare".
Asked by lawmakers if Russia could expand military cooperation with Cuba, Venezuela and Nicaragua as part of its retaliatory measures, Lavrov responded that Moscow has close ties with those countries in the Western Hemisphere and is seeking to deepen them.
He noted Putin spoke by phone with the three nations' leaders last week and they agreed to "consider ways of further deepening our strategic cooperation".
Earlier this month, Lavrov's deputy pointedly refused to rule out the deployment of Russian military assets to Cuba and Venezuela if Moscow's security demands aren't met.
The countries' defence ministries were planning more contacts to bolster military cooperation, Russia's ambassador to Cuba Andrei Guskov told the Interfax news agency. Nato said this week it was bolstering its deterrence in the Baltic Sea region and the US ordered 8500 troops on higher alert for potential deployment to Europe. Western nations have also sent planeloads of weapons to help Ukraine strengthen its defences.
Amid the escalating tensions, Ukrainian officials have sought to calm nerves.
Ukraine's Foreign Minister Dmytro Kuleba said that while the concentration of Russian troops near Ukraine poses a threat, "their number is now insufficient for a large-scale offensive".
"They are still missing some key military elements and systems to mount a big, full-scale offensive," Kuleba told reporters.
As others have pointed out, he noted that causing alarm could be an end in itself. Russia, he said, hopes to destabilise Ukraine by "spreading panic, raising pressure on Ukraine's financial system and launching cyberattacks",
"President Putin would be happy to see that plan succeed so that he doesn't even need to turn to military force to put Ukraine in a vulnerable position."
His comments were latest from Ukrainian officials seeking to reassure their citizens.
Speaking late Tuesday in speech to the nation, President Volodymyr Zelenskyy said Ukraine was "strong enough to keep everything under control and derail any attempts at destabilisation".
Amid the tensions, the US, Britain, Australia, Germany and Canada have moved to withdraw some of their diplomats and dependents from Kyiv, a move that Ukrainian President Volodymyr Zelenskyy sought to play down Tuesday as part of a "complex diplomatic game".
On Wednesday, the US Embassy in Kyiv urged all US citizens visiting Ukraine to consider leaving the country now, pointing out that the security situation "continues to be unpredictable due to the increased threat of Russian military action and can deteriorate with little notice".
Several rounds of high-stakes diplomacy have failed to yield any breakthroughs, but another attempt was going forward Wednesday.
Presidential advisers from Russia, Ukraine, France and Germany were in Paris to discuss ways to revive a stalled peace agreement for eastern Ukraine.
In 2014, following the ouster of a Kremlin-friendly president in Kyiv, Moscow annexed Ukraine's Crimean Peninsula and threw its weight behind a separatist insurgency in the country's eastern industrial heartland. Fighting between Ukrainian forces and Russia-backed rebels has killed more than 14,000 people, and efforts to reach a settlement have stalled.
Kremlin spokesman Dmitry Peskov said Moscow expects a "good frank" talk at the Paris meeting.
Russia accuses Ukraine of planning to retake the areas controlled by the rebels — something Kyiv denies. On Wednesday, Lavrov again alleged the West is encouraging Ukraine to launch an offensive and rejected talk about an imminent Russian invasion as "hysterics".
Andrei Turchak, head of the Kremlin's main political party, United Russia, suggested that Moscow respond to the delivery of Western weapons to Ukraine by sending munitions to the rebels. Since the start of the conflict, Russia has been accused of sending troops and weapons to the separatists, something it has denied.
The US and its allies also have threatened harsh sanctions if Moscow sends its troops into Ukraine, but they have given few details.
On Tuesday, US President Joe Biden said Putin "continues to build forces along Ukraine's border", and an attack "would be the largest invasion since World War II. It would change the world". He warned that there would be serious economic consequences for Putin, including personal sanctions, in the event of an invasion.
Asked to comment on Biden's statement, Peskov pointed out that Putin and other top officials don't have assets in the West but reaffirmed that such US sanctions would be "politically destructive" for bilateral ties.
Britain also promised sanctions, and Foreign Secretary Liz Truss has urged European nations to do more to support Ukraine. The UK has sent anti-tank weapons to Ukraine, though it has ruled out sending combat troops.
"We'll be legislating to toughen up our sanctions regime and make sure we are fully able to hit both individuals and companies and banks in Russia in the event of an incursion," she told the BBC. "What's important is that all of our allies do the same."
German Foreign Minister Annalena Baerbock stressed at a meeting with her Dutch counterpart in Berlin that the European Union's goal "is and remains the defence of Ukraine's sovereignty and territorial integrity".
"Any further aggression by Russia against Ukraine would have serious consequences. Politically, strategically, and equally economically and financially," Baerbock said.