"The explosion occurred in the industrial zone in Donetsk’s Kuibyshevsky District. It was most likely the hit of an artillery shell," a militia spokesman said.

Eyewitnesses said the explosion could be heard in all districts of the city.

The militia said it does not have information about those injured and damage caused by the blast.

"Accurate data about what happened will be available by morning," the militia said.

Thousands have been killed and hundreds of thousands of people have fled Ukraine’s embattled east as a result of clashes between Ukrainian troops and local militias in the Donetsk and Lugansk regions during Kiev’s military operation, conducted since mid-April 2014, to regain control over parts of the breakaway territories, which call themselves the Donetsk and Lugansk People’s republics.