The Kremlin has reportedly amassed more than 100,000 soldiers on the border with Ukraine, leading to fears about its intentions.
Amid such concerns, the US secretary of state Antony Blinken landed in Europe on Wednesday for talks with Russian officials this week.
Speaking in Kiev, the senior Biden administration official said the US would continue to pursue diplomatic channels to try to prevent Russian aggression against Ukraine.
After meeting Ukrainian president Volodymyr Zelensky in Kiev on Wednesday, the US secretary of state will travel to Berlin to talk to other allies on Thursday.
Mr Blinken will then meet Russian foreign minister Sergei Lavrov in Geneva on Friday to discuss the perceived threat to stability in Europe.
Talking about the hurriedly arranged visit, White House press secretary Jen Psaki highlighted the urgent need for diplomacy. “We’re now at a stage where Russia could at any point launch an attack in Ukraine,” she said.
Russia has created the crisis through its aggressive build-up of troops on the Ukrainian border, she added. Russia denies such accusations and says it can do what it likes with soldiers inside its own borders.
Ms Psaki’s comments come as Russia has sought to further increase its military presence in the region. The Kremlin is moving soldiers from the far east to Belarus for joint war drills with the Lukashenko regime, which are expected to start on 10 February.
To prepare against a possible invasion, Ukraine’s defence ministry said on Tuesday that it was accelerating its deployment of 130,000 reserves to augment its 246,000-strong military.
Earlier this week, the UK dispatched anti-tank weapons to Ukraine to help bolster its defences, while the US reportedly signed off $200m (£147m) in military aid to the country.
However, this support is unlikely to provide much comfort to leaders in Kiev, given the vast disparity in military strength between Ukraine and Russia.
Referring to this issue, Vadym Prystaiko, Ukraine’s ambassador in Britain, told the BBC this week it was problematic that Ukraine was not part of Nato.
“We are not part of this family and we are facing the biggest army in Europe by ourselves,” he said.
Ukraine’s latest assessment of Russian troop numbers – shared with CNN – puts the number deployed in the region at 127,000, including 21,000 personnel in sea and air divisions.
Last week, talks between Russia and the west over Ukraine broke down as a result of broad disagreement. Moscow had wanted Nato to withdraw troops from its neighbouring countries and to prevent new members from joining the defensive alliance – stipulations that were ruled out by the west.
On Wednesday, British minister James Heappey warned that tens of thousands of people would die if Russia were to start an “extraordinarily stupid” conflict with Ukraine.
Additional reporting by AP
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