New Delhi, Feb. 20: The Indian Embassy in Ukraine on Sunday advised all Indian nationals, whose stay is not deemed essential, to temporarily leave Ukraine. Indian students were also advised to also get in touch with respective student contractors for updates on chartered flights.

Earlier in the day, Multiple explosions could be heard late Saturday and early Sunday in the centre of the separatist-controlled city of Donetsk in eastern Ukraine, a Reuters reporter said. The origin of the explosions was not clear. Meanwhile, UK Prime Minister Boris Johnson told the BBC that the plans that the West is seeing at Ukraine’s border suggest that a Russian invasion could be “the biggest war in Europe since 1945 in terms of sheer scale”.

Almost 2,000 ceasefire violations were registered in eastern Ukraine by monitors for the Organisation for Security and Cooperation in Europe Saturday, a diplomatic source told Reuters Sunday. The Ukrainian government and separatist forces have been fighting in eastern Ukraine since 2014. An upsurge in shelling has thrust the region to the centre of tensions between Moscow and the West over a Russian military buildup near Ukraine.

Russia's strategic nuclear forces held exercises overseen by President Vladimir Putin Saturday, and Washington accused Russian troops massed near Ukraine's border of advancing and being "poised to strike".

Satellite imagery taken this week shows military activity in multiple locations across Belarus, the annexed Crimea region of Ukraine and western Russia near Ukraine's border. US-based Maxar Technologies, which has been tracking the buildup of Russian forces for weeks, said the images show recent helicopter deployments, consisting of both troop transport and ground attack helicopters, at multiple locations close to the border.

The US issued some of its starkets, most detailed warnings yet about how a Russian invasion of Ukraine might unfold, and its Western allies went on high alert for any attempts by the Kremlin to create a false pretext for a new war in Europe.

US President Joe Biden sounded unusually dire Thursday, as he warned that Washington saw no signs of a promised Russian withdrawal — but instead saw more troops moving toward the border with Ukraine,  indicating Moscow could invade within days.

Western fears focus on an estimated 150,000 Russian troops — about 60% of Russia's overall ground forces — posted around Ukraine's borders. The Kremlin insists it has no plans to invade, but it has long considered Ukraine part of its sphere of influence and NATO's eastward expansion an existential threat. A key demand in this crisis is that NATO promise never to allow Ukraine to join.-Agencies