Kiev, Aug 15 (IANS): At least 16 people were killed in eastern Ukraine over the past one day as government forces stepped up their offensive against independence-seeking rebels, authorities said Friday.

The conflict has reached a critical stage in Donetsk city, where heavy shelling Thursday afternoon killed 11 civilians and injured eight others.

Donetsk City Council said the shelling also damaged several electricity substations and destroyed 20 private houses, Xinhua reported.

The rebels have repeatedly accused government forces of using rockets against civilians, but Ukrainian officials deny the charge, saying that the shelling in populated areas is carried out by separatists to incriminate government troops.

Fierce battles were also reported in the neighbouring Gorlovka town and in the city of Lugansk though rebel-held Donetsk and its outskirts still remain the epicentre of clashes.

Over the past 24 hours, at least five Ukrainian soldiers were killed in encounters with rebels, according to Andrei Lysenko, a spokesman for the National Security and Defence Council.

However, some local military experts believe that Ukrainian officials tend to downplay the number of casualties among the government troops.

According to regional authorities, at least 839 civilians have been killed in Donetsk region and around 1,500 in Lugansk region since mid-April, when Kiev started its military operation to retake cities and towns controlled by insurgents.