Russia has drilled 700 snipers near the border with Ukraine amid growing fears President Vladimir Putin plans to invade.
It comes as Kiev today warned Moscow now has more than 94,000 troops in the disputed region and is plotting a 'large scale escalation' in January.
Ukrainian Defence Minister Oleksii Reznikov told lawmakers on Friday that intelligence from the border shows 'the possibility of a large-scale escalation from Russia exists'.
Tensions over the neighbouring states' border have deepened in recent weeks over the buildup and Ukrainian and Western officials have voiced alarm, saying they fear it could herald an invasion.
Moscow has insisted it has no intention of invading and accused Ukraine and its Western backers of fabricating claims to cover up their own allegedly aggressive designs.
But Russian soldiers have been pictured conducting sniper exercises with servicemen lying on the ground, dressed in white, in snowy conditions.
Russian state media reported the drills, taking place in three of the four Russian regions that border Ukraine, involved teaching soldiers sniper camouflage, long distance shooting and hand-to-hand combat. The shooters were practicing with the Strelets-M reconnaissance, command and communications system including a portable computer designed to be worn in the battlefield.
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Servicemen from the sniper units of the Western Military District's combined army have begun to conduct large-scale exercises as part of a training camp in Voronezh, Belgorod, Bryansk and Smolensk regions,' a military statement said, adding that more than 700 people were involved.
Meanwhile Rossiya 1 channel reporter Andrey Rudenko posted a video which he said showed Ukrainian armed forces shelling pro-Kremlin rebel-held Donetsk and Dokuchaevsk.
He claimed the footage showed Ukrainian soldiers shooting from an infantry fighting vehicle and later shelling the northwest of Donetsk city.
Responding to the video, Denis Pushilin, leader of the self-proclaimed Donetsk People's Republic told Russian state channel Rossiya 1: 'I do not rule out that we will turn [for help] to Russia and Belarus... We will act according to the situation.'
He added that Belarus dictator Alexander Lukashenko has made clear he will back Russia in any military conflict. Ukraine's Reznikov told lawmakers on Friday the 'most probably time' for a Russian attack would be at the 'end of January'.
The minister noted an escalation 'is a probable scenario, but not certain, and our task is to avert it.'
Russia and Ukraine have remained locked in a tense tug-of-war after Russia annexed Ukraine's Crimean Peninsula in 2014 and threw its weight behind a separatist insurgency in Ukraine's eastern industrial heartland, known as the Donbas. More than 14,000 people have died in the fighting.
Repeated reports about Russia building up troops near Ukraine this year ignited concerns about the conflict intensifying, with tensions growing in recent weeks.
Russia traded fresh accusations and threats with Ukraine, the United States and its NATO allies this week. The West threatened the Kremlin with the toughest sanctions yet if it launches an invasion of Ukraine.
Russia, seeing new US and European support for Ukraine's military, sternly warned that any presence of NATO troops and weapons on Ukrainian soil represents a 'red line.'
The Kremlin also expressed concern that Ukraine might use force to reclaim control of the country's rebel east.
Reznikov said Ukraine wouldn't do anything to provoke Russia but is prepared to respond in case of an attack.
'Ukraine is most interested in political and diplomatic resolution,' the defence minister said.
Senior Moscow senator Vladimir Dzhabarov warned that Russia may send in troops to support Russian passport holders in separatist regions of Ukraine
But senior Moscow senator Vladimir Dzhabarov has warned that Russia may send in its troops to support half a million Russian passport holders living in these two rebel held regions, also known as Donbas.
'We may look at this matter in the event of a direct appeal, and if there is a threat to the lives of the people,' said Dzhabarov, deputy chairman of the upper house of parliament's International Affairs Committee.
'Half a million citizens of Donbas have become Russian citizens,' he said, referring to a drive by Moscow to give passports to people living in eastern Ukraine.
'Of course, we cannot abandon our compatriots.'
He said: 'I hope it won't come to that, and that the guarantors of the Minsk agreements [on a peaceful settlement in these regions] - both Germany and France - will calm [Ukraine] president Volodymyr Zelensky's regime, which, is in such a position that it's ready to try any provocation, or to drag Russia into some kind of armed conflict.
'I hope it doesn't come to that, and that it will be possible to resolve this matter in some kind of peaceful way after all.'
Russia claimed today its radars had tracked over 30 foreign spy planes near its borders in the past week.