Initial reports say people poured out of offices in the centre of the city after an evacuation warning sounded.
More than 100 lorries carrying Russian aid are heading towards a rebel-controlled border crossing in the Luhansk region.
There is continuing confusion over their final destination.
Russia has dismissed as absurd claims that its convoy is a pretext to send military supplies to the rebels.
But Ukraine has said the convoy must be inspected by international monitors before it can be let in.
– Source: aitonline.tv
