The Russian buildup has caused growing concern in the West in recent days, with the United States saying that troop levels are at their highest since 2014, when war first broke out with Moscow-backed separatists.

Asked by a US House of Representatives committee on the recent increase in tensions between the neighbors, General Tod Wolters said it was a "great concern."

But when a lawmaker asked him to evaluate the probability of a Russian invasion of Ukraine in the next few weeks, Wolters said it was "low to medium."

"My sense is that with the trend that I see right now, that the likelihood of an occurrence will start to wane," said the head of US European Command, which also commands NATO's allied forces.

For several weeks, clashes have increased between Kiev and pro-Russian separatists in eastern Ukraine, while tens of thousands of Russian troops have been deployed nearby, raising fears of a major military operation.

The Ukrainian government is also worried that Moscow is seeking to provoke a situation that would justify an armed operation.

Western countries have warned Moscow against displays of force, and Ukrainian President Volodymyr Zelensky will meet his French counterpart, Emmanuel Macron, in Paris on Friday.

Germany's Chancellor Angela Merkel will participate in the talks via videoconference.

NATO allies 'stand' with US on Russia sanctions
Brussels (AFP) April 15, 2021 - NATO allies on Thursday backed the United States' decision to impose sanctions on Russia and expel its diplomats over what they said were Moscow's "destabilising activities."

"NATO Allies support and stand in solidarity with the United States, following its 15 April announcement of actions to respond to Russia's destabilising activities," the statement said.

"Allies are taking actions individually and collectively to enhance the Alliance's collective security," it said.

NATO members cited a "sustained pattern" of Russian behaviour, from aggression against Ukraine to interference in the US presidential election and cyber attacks.

"The United States and other Allies assess that all available evidence points to the responsibility of the Russian Federation for the SolarWinds hack," the statement said.

The alliance also condemned the nerve agent attack on Kremlin critic Alexei Navalny, which it blames on Moscow, and said it was concerned by reports Russia had encouraged attacks againsts its troops in Afghanistan.

"Allies will continue to work in close consultation to address Russia's actions, which constitute a threat to Euro-Atlantic security," the statement said.

"We call on Russia to cease immediately its destabilising behaviour, and to uphold its international obligations."

The US announced economic sanctions against Russia on Thursday and the expulsion of 10 diplomats in retaliation for what Washington says is the Kremlin's US election interference, a massive cyber attack and other hostile activity.

President Joe Biden's executive order "sends a signal that the United States will impose costs in a strategic and economically impactful manner on Russia if it continues or escalates its destabilising international action," the White House said.