Ukraine’s Russian-backed breakaway eastern territories have ordered military mobilisations amid a deadly escalation in fighting.
Men of fighting age in the self-declared people’s republics of Donetsk and Luhansk are being put on stand-by.
US President Joe Biden says he is convinced Russia will invade Ukraine, an allegation Moscow denies.
Western nations have accused Russia of trying to stage a fake crisis in the eastern regions as a pretext to invade.
International monitors report a “dramatic increase” in attacks along the line dividing rebel and government forces.
A Ukrainian soldier was killed by shelling on Saturday morning, the first such death reported in weeks.
Mr Biden’s Defence Secretary, Lloyd Austin, said Russian forces were beginning to “uncoil and move closer” to the border with Ukraine.
In the German city of Munich, US Vice-President Kamala Harris told a security conference that if Russia did invade, the US and its allies would impose a “significant and unprecedented economic cost”, targeting its financial institutions and key industries, as well as those who aided and abetted such an invasion.
The US estimates there are 169,000-190,000 Russian personnel massed along Ukraine’s borders, a figure that includes separatist fighters in Donetsk and Luhansk.
Russian President Vladimir Putin, who oversaw major drills of Russia’s strategic nuclear missile forces from Moscow on Saturday, has said the situation in eastern Ukraine is deteriorating.
He said he remained willing to discuss the crisis with Western leaders, but accused them of ignoring Russia’s security concerns.
Ukraine, a former Soviet republic with historic ties to Russia, is not a member of Nato or the European Union but has close relations with both.
Accurate figures are difficult to establish but as many as 3.5 million people live in the two rebel territories, which broke away in 2014 after Ukraine’s pro-Russian government was overthrown. Since then, at least 720,000 have acquired Russian citizenship, according to Russian media.
BBC
