KEIV — High-stakes diplomacy continues in a bid to avert a war in Eastern Europe as the Russian military build-up on its border with Ukraine continues to pose a threat.

The French president and the German chancellor will head to Moscow and Keiv in the coming weeks, adding to diplomatic efforts to try to deter Russian President Vladimir Putin from launching an invasion and find a way out of the growing tensions.

In Brussels, EU chief Ursula von der Leyen warned in an interview with Euronews that Russia will face "severe consequences" and "massive costs" if there is any military aggression against Ukraine.

Meanwhile, the first of the 1,700-unit-strong US troop contingent arrived in Poland on Saturday afternoon, following US President Joe Biden's promise to send military support to Europe earlier in January.

Chinese President Xi Jinping backed Russian counterpart Vladimir Putin in his standoff with the West over Ukraine as the two leaders met before the Beijing Olympics opening festivities.

The US says Russia has amassed more than 100,000 troops near Ukraine's border and has warned it could invade.

Moscow has denied it wants a war. It says NATO expansion near its borders poses a national security threat and wants a pledge that Ukraine — formerly part of the Soviet Union — will never join the transAtlantic military alliance.

Diplomatic moves to ease the crisis are set to continue next week when French President Emmanuel Macron heads to Moscow and Keiv for talks. Macron spoke by phone to US President Joe Biden on Wednesday to update Washington on his diplomatic push.

And on Thursday night, the French leader talked to Putin and Ukrainian President Volodymyr Zelenskyy about the ways to “identify elements that could lead to de-escalation” and “conditions for strategic balance in Europe, which should allow for the reduction of risks on the ground and guarantee security on the continent”.

While France is a major player in NATO and is moving troops to Romania as part of the alliance’s preparation for possible Russian action, Macron has also been actively pushing for a dialogue with Putin and has spoken to him several times in recent weeks.

Macron's office said the two would hold a one-on-one meeting this Monday.

Macron is not the only European leader heading east. German Chancellor Olaf Scholz will visit Ukraine and Russia in mid-February, adding to diplomatic efforts to resolve the crisis centering on Russian troops massed near Ukraine’s borders.

Government spokesman Wolfgang Buechner said Friday that Scholz will travel to Keiv on Feb. 14 and Moscow on the next day. The trip will follow a previously planned meeting in Washington with Biden.

Buechner said the German government is consulting with France and Poland on a meeting between the three countries' leaders, but a date has not yet been set. He said that, on Thursday, Scholz will welcome the leaders of the three Baltic states of Lithuania, Latvia and Estonia to the chancellery.

Foreign Ministry spokeswoman Andrea Sasse said that Foreign Minister Annalena Baerbock will visit Ukraine on Monday and Tuesday, including a trip to the “contact line” with rebel-held areas in eastern Ukraine.

After weeks of talks in various diplomatic formats have led to no significant concessions by Russia and the US, it is unclear how much impact the trips will have. But Ukraine's Foreign Minister Dmytro Kuleba said on Friday that “top-level visits seriously reduce challenges in the sphere of security and upset the Kremlin's plans.”

Separately from Macron and Scholz, Turkish President Recep Tayyip Erdoğan has offered to mediate talks between Russia and Ukraine. Erdoğan visited Keiv this week and, upon returning to Turkey, charged that Western leaders have failed to positively contribute to resolving tensions between Russia and Ukraine.

"I would like to reiterate that we continue to support the sovereignty and territorial integrity of Ukraine, including in Crimea," he stated after his meeting with Ukrainian President Zelenskyy.

"As I have emphasized before, Turkey is prepared to undertake its part in order to end the crisis between two friendly nations that are its neighbors in the Black Sea."

"As Turkish people, instead of fueling the fire, we act with the logical aim of reducing the tensions," Erdoğan lamented. Erdoğan also said that Zelenskyy strongly supports a Turkish proposal for mediation to reduce tensions between the two nations.

“Unfortunately, the West has not contributed anything toward a solution to this issue,” Erdoğan said. “They are just creating obstacles.”

Russia will face "severe consequences" and "massive costs" if there is any military aggression against Ukraine, European Commission President Ursula von der Leyen has warned in an interview with Euronews.

"We should never give up to work on diplomacy," said von der Leyen. "But we are very clear that — in case that there's any further military aggression of Russia against Ukraine — this will have severe consequences and massive costs for Russia."

She said the EU had also prepared a "robust" and "very comprehensive" package of sanctions for Moscow if the worst-case scenario comes to pass.

Von der Leyen's comments come after a high-level meeting this week between Putin and Hungarian Prime Minister Viktor Orbán in Moscow. During a joint press conference, Orbán spoke of sanctions as an "unsuccessful tool" that is "doomed to failure".

"There is unity and a very strong alignment within the European Union. We are in constant contact," von der Leyen said when asked about Orbán's remarks.

Putin got the support of his Chinese counterpart amid fears in the West that Moscow is preparing for military action against Ukraine.

Putin met with Xi before the opening ceremony of the Winter Olympics in Beijing, and the leaders issued a joint statement highlighting what it called “interference in the internal affairs” of other states, as Russia amasses troops on its border with Ukraine.

“Some forces representing a minority on the world stage continue to advocate unilateral approaches to resolving international problems and resort to military policy,” it read in what is seen as a reference to the US and its allies.

“The Chinese side is sympathetic to and supports the proposals put forward by the Russian Federation to create long-term legally binding security guarantees in Europe,” the statement read.

The meeting came amid fears in the West that Moscow could be looking for a way to initiate the conflict with Keiv. On Thursday, the US accused the Kremlin of an elaborate plot to fabricate an attack by Ukrainian forces that Russia could use as a pretext to take military action against its neighbor.

Poland’s president was the only European Union leader to attend the Winter Olympics opening Friday, in what his office said was a bid to maintain good ties with China and lobby for an easing of Russia-Ukraine tensions.

President Andrzej Duda is scheduled to meet with Chinese leader Xi on Sunday, his office said, but is not expected to meet Putin, who is also in Beijing.

Other EU leaders followed the US, the UK, Australia and Canada, among others, in a stated or unstated diplomatic boycott of the Games due to China’s human rights record — while allowing their athletes to compete.

Duda’s foreign policy advisor Jakub Kumoch said the president wants to seize “certain diplomacy chances” that the gathering of many leaders in Beijing offers. “The goal of these talks is to encourage the interlocutors to play an active role in leading to Russia-Ukraine talks,” Duda’s press office said.

Poland’s Defense Ministry said additional US troops arrived in Poland after President Biden ordered the deployment of 1,700 soldiers there amid fears of a Russian invasion of Ukraine.

The ministry said US planes with equipment and logistics troops are landing in order to prepare for the arrival of the main force — elements of the 82nd Airborne Division from Fort Bragg, North Carolina.

"The first troops have arrived at Jesionka airport in the south-east," Maj. Przemyslaw Lipczynski said, adding that the main forces of a 1,700-strong US contingent were due to arrive "soon".

The Rzeszow-Jasionka airport is some 90 kilometers from Poland's border with Ukraine. Some 4,000 US troops have been stationed in Poland since 2017 on a rotation basis.

Amid the simmering tensions between their two countries, five-a-side football teams from Russia and Ukraine face one another in the semifinals of the Futsal European Championships in Amsterdam.

European soccer's governing body, UEFA, has ensured that Ukrainian and Russian teams are not drawn to play one another since 2014, the year Russia annexed Crimea.

But in a written statement, the European football governing body said that the measure to keep teams apart “for obvious reasons cannot apply to the entire knockout stages of tournaments like the UEFA Futsal EURO 2022”.

“UEFA expects fair play by the two teams, on and off the pitch,” the organization said, adding that local organizers of the tournament in the Dutch capital are working “to ensure that the event will take place safely and, in this respect, is working on implementing specific security plans”.

Meanwhile in Washington, US officials said a plan for a fake attack on Russian territory or Russian-speaking people was described in declassified intelligence shared with Ukrainian officials and European allies in recent days.

It was the latest example of the Biden administration divulging intelligence findings as a tactic to stop Russian disinformation efforts and foil what it says is Putin’s attempt to lay the groundwork for military action. However, some have questioned the veracity of US claims due to its hesitance to provide concrete evidence.

Russian officials have rejected the allegations. Foreign Minister Sergey Lavrov on Friday spoke about the "absurdity" of the claims, and Kremlin spokesman Dmitry Peskov recommended reporters "not to take anyone's word for it, especially the (US) State Department's, when it comes to these issues".

Ukraine's foreign minister said Friday that Washington shared the information with Keiv and that it did not surprise Ukrainian authorities. "Since 2014, we have seen many insidious actions by Russia. We have seen that nothing stops them from fabricating something and accusing Ukraine of something," Kuleba told reporters.

In recent weeks, the White House has said that US intelligence shows Russia has launched a malign social media disinformation campaign against Ukraine and has dispatched operatives trained in explosives to carry out acts of sabotage against Russia's own proxy forces.

The UK has divulged intelligence findings that it says show Moscow plotted to install a pro-Russian puppet government in Ukraine. — Euronews