Multiple explosions have been heard this morning in the centre of the separatist-held city of Donetsk in eastern Ukraine, as tensions continue to rise.
A loudspeaker in the area asked citizens to exercise caution but the origin of the explosions is not clear.
The West remains convinced Vladimir Putin is poised to order an imminent invasion of Russian troops, who are lying in wait on the border.
It comes after explosions could also be heard late last night in the city - as well as earlier that morning in the north, according to witnesses.
As well as that, reports suggested that the Kyiv district was also hit by projectiles.
There were nearly 2,000 ceasefire violations between the two sides on Saturday alone.
Russia and Ukraine have been at loggerheads since 2014 but the recent increase in shelling along the frontline has only helped to fuel fears of a full-scale war.
Separatist troops leader Denis Pushilin had ordered a full mobilisation of rebel troops in the area.
Violence has been flaring up in the neighbouring Luhansk, including a car being supposedly bombed on Friday.
Donetsk and fellow separatist-held “republic” Luhansk this week ordered the evacuation of all civilians, except men between 18 and 55 who are expected to “take up arms” in the event of a so-called Ukrainian attack.
Those who fled to the Rostov region were met with bemusement by locals who refused to house them, according to videos on the Telegram social media site.
As many as 190,000 Russian troops are estimated to be camped at the border, but Putin has always denied he wished to attack.
The Kremlin released footage of tanks supposedly being pulled from the border and claimed personnel were being taken back to base after drills were complete.
But Nato officials refused to believe there was to be a major withdrawal and days later it was reported Moscow had actually moved another 7,000 troops to the front.
Putin and Belarusian leader Alexander Lukashenko yesterday watched nuclear drills from his situation centre in Moscow.
Boris Johnson claims - after reviewing evidence - Russia is planning "the biggest war in Europe since 1945".
Speaking to the BBC, the British PM added that "all the signs are that the plan has already in some senses begun".
He said Putin will invade Ukraine before encircling the capital of Kiev.
Mr Johnson was speaking from the annual Munich Security Summit, where he met with Nato allies.
But the Tory leader and other world leaders still hope it may still be possible to avoid war.
He added: "People need to understand the sheer cost in human life that could entail.
"I'm afraid that that is what the evidence points to, there's no burnishing it.
"The fact is that all the signs are that the plan has already in some senses begun."
