The United States on Wednesday deployed several thousand troops to bolster NATO forces in eastern Europe, as the leaders of France and Germany flagged trips to Moscow to address Western fears of an invasion of Ukraine.
With Russia refusing to pull back 100,000 troops poised on Ukraine's borders, 1,000 US soldiers in Germany are being sent to Romania, and another 2,000 stationed in the United States are being flown to Germany and Poland.
"As long as (President Vladimir Putin) is acting aggressively, we are going to make sure we reassure our NATO allies in eastern Europe that we're there," President Joe Biden said after the deployments were announced.
In response, Russian Deputy Foreign Minister Alexander Grushko said the move would make it harder for a compromise between the two sides, calling the US deployments "destructive steps, which increase military tension and reduce scope for political decision."
Western powers have been engaged in intense diplomatic efforts -- coupled with the threat of sanctions against Putin's inner circle -- to deter what they fear to be a looming invasion of ex-Soviet Ukraine, despite strenuous denials from Moscow.
Germany's Chancellor Olaf Scholz announced Wednesday he would soon travel to Moscow to discuss the crisis, while France's President Emmanuel Macron said a similar trip may be in the cards -- depending on upcoming talks with other world leaders.
Biden and Macron pledged to coordinate their response to the crisis in a phone call on Wednesday, while the French leader's office said he would be talking to Putin again on Thursday evening.
In Washington, Pentagon spokesman John Kirby stressed that the US troop movements were to demonstrate commitment to the NATO alliance, and that no American soldiers would be sent to fight in Ukraine, which is not a NATO member.
But that is unlikely to assuage Putin, who has accused the United States and NATO of seeking to "contain" Russia by placing troops and strategic arms on its border.
"Ukraine itself is just a tool to achieve this goal," Putin said Tuesday in his first major comments in weeks on the crisis.
Putin has demanded guarantees that Ukraine will not join NATO, and has implicitly threatened the former Soviet state with the massive military buildup.
Russia also wants NATO and the United States to foreswear the deployment of missile systems near Russia's borders and to pull back NATO forces in eastern Europe.
Putin has left the door open to talks, saying he was studying Western proposals set out last month in response to Russia's demands, and that he hoped that "in the end we will find a solution."
But in a phone call with British Prime Minister Boris Johnson on Wednesday, he noted "the unwillingness of NATO to adequately respond to the well-founded Russian concerns," the Kremlin said.
The Kremlin also claimed it had China's support in the standoff -- backing that would be demonstrated when Putin meets President Xi Jinping in Beijing on Friday.
- Diplomatic efforts -
Dutch Prime Minister Mark Rutte was the latest NATO leader to visit Kyiv Wednesday in a show of support, meeting with Ukrainian President Volodymyr Zelensky.
After the talks, Zelensky said Ukraine was focused "only on peace," but insisted it has the right to defend itself.
Rutte said it was "essential for dialogue to continue" between Russia and the other players.
Citing leaked documents, the Spanish newspaper El Pais reported that the Western proposals to Russia -- set out in letters by NATO and the United States last month -- include arms control and trust-building measures to defuse the situation.
While a guarantee against Ukraine joining NATO was not offered, the documents proposed commitments by the United States and Russia "to refrain from deploying offensive ground-launched missile systems and permanent forces with a combat mission in the territory of Ukraine," El Pais reported.
"We did not make this document public," Kirby said, without denying its authenticity.
He said it confirmed that "NATO and its partners are unified in their resolve and open to constructive and serious diplomacy."
- 'Imminent' invasion? -
In a change of language, the White House said Wednesday that it would no longer refer to a Russian invasion of Ukraine as "imminent" -- explaining that the word implied Putin had already made a decision to attack.
Press Secretary Jen Psaki's use of the word last week drew criticism from Ukraine.
Psaki said that she usually referred to Putin putting troops in a position where they "could invade at any time."
Tensions with the West have been further aggravated by plans for joint military exercises between Russia and neighboring Belarus, where Washington claims Moscow is preparing to send 30,000 troops.
Video footage released by the Russian defense ministry showed tanks speeding across snowy fields in Belarus and combat helicopters flying overhead as units from both countries practiced ahead of the February 10-20 drills.
NATO welcomed the new US troop deployment, with Secretary-General Jens Stoltenberg saying the alliance "will do whatever is necessary to protect and defend all allies."
Erdogan eyes Ukraine summit with Putin
Turkish President Recep Tayyip Erdogan visits Kyiv on Thursday in a bid to set the stage for a three-way summit with Russia's Vladimir Putin aimed at avoiding war in Ukraine.
The veteran Turkish leader's talks with his Ukrainian counterpart Volodymyr Zelensky come with Kyiv hesitant to accept US warnings that President Putin is preparing to invade.
Erdogan has also tried to talk down the prospects of war while pursuing his own diplomatic track separate from those followed by European leaders.
"We want peace to prevail in our region, and for this we are ready to do anything," Erdogan said last month.
But his attempts to host a peace summit between Putin and Zelensky have been stymied by Kremlin anger over Turkey's supply of combat drones to Kyiv that played a crucial role in the 2020 conflict over Nagorno-Karabakh.
Putin warned Erdogan in December that Kyiv was trying to disrupt a peace agreement for its two eastern separatist provinces with "provocative" military actions that included the use of Turkish drones.
- 'Offering to mediate' -
Ukraine has suffered from a simmering conflict across its mostly Russian-speaking industrial east since a 2014 revolution set the former Soviet republic on a firmer pro-Western course.
Zelensky has called Russia's positioning of new forces across Ukraine's eastern and northern borders -- as well as in the annexed Crimea peninsula -- part of a Kremlin diplomatic power play with NATO and Washington.
Officials in Kyiv worry that Western talk of an imminent Russian invasion is frightening investors and doing further damage to Ukraine's struggling economy.
But Zelensky has warmly welcomed visits from a string of Western leaders who have reaffirmed their support for Ukraine's territorial integrity and right to set its own course.
Erdogan is officially going to Kyiv to attend an economic forum at which the two leaders are expected to announce a new free trade deal.
Analysts believe he will adopt a nuanced approach that positions Turkey as a more neutral mediating partner.
"Ankara has sought to maintain close relations with both Moscow and Kyiv," the Foreign Policy Research Institute's Middle East Program director Aaron Stein told AFP.
"So given the present reality, Erdogan has fallen back on a staple of his government's rule: offering to mediate."
- Special relationship -
Erdogan enjoys a special relationship with Putin -- dubbed by analysts as "competitive cooperation" -- that allows them to compartmentalise their disputes.
Yet the Kremlin has given a decisively cool reception to Erdogan's mediation offers in the past month.
Erdogan first raised the idea of flying to Moscow from Kyiv. The Kremlin said it was unaware of such plans.
The Turkish leader then extended a formal invitation for Putin to come to Turkey.
The Kremlin said last week that Putin would be happy to visit "once the epidemiological situation and the schedule allows".
Analysts believe Putin is not interested in outside mediation because of his desire to be treated as an equal by Washington.
But Erdogan has tried to show he is receptive to Putin's stated concerns about the threats posed by NATO's expansion in the years after the Soviet Union's collapse.
"There is a need to listen to Russia and eliminate their reasonable security concerns," Erdogan said last week.