Explosions have been heard around an aircraft repair plant, about 5km from the city centre.
Up until now western Ukraine has been quieter than the rest of the country and has been used as a safe haven, a hub for people fleeing and a supply route, both for humanitarian and military purposes.
However, according to the latest intelligence from the UK Ministry of Defence, counter attacks by Ukraine soldiers means Russia can’t get supplies to its forward lines.
The BBC’s Hywel Griffith reports.
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