Updated

Fighting in eastern Ukraine has escalated, killing at least three people overnight, injuring many more and trapping 200 coalminers underground.

The press office of the Ukrainian government's operation in the east said on Tuesday that heavy shelling around Avdiivka on the northern outskirts of the separatist stronghold of Donetsk has killed at least three troops and injured 20 more. The operation headquarters also reported an unspecified number of civilian casualties.

Fighting, which appears to be the worst in many months, is concentrated around the Donetsk suburb of Avdiivka, home to a giant coking plant. Its director said on Monday that preparations were being made to stop production after heavy shelling.

In Donetsk, the rebels' Donetsk News Agency said an electric power cut had trapped more than 200 coalminers fellow ground.