AT LEAST three civilians were killed and another 10 wounded in today's shelling of Donetsk.

The main rebel stronghold in eastern Ukraine is besieged by government forces and the Donetsk city council said four apartment buildings in the southern part of the city had been damaged by artillery barrages.

Shocked residents gathered in the morning and some left flowers on the pavement to commemorate the victims.

Ukrainian officials have adamantly denied that government forces have been shelling populated areas. However, witness testimony has pointed to the contrary.

Overnight explosions were also heard elsewhere in Donetsk, but there have been no reported casualties in the area.

Meanwhile, the head of Nato warned Russia to “step back from the brink” of war by pulling its troops back from the Ukrainian border. The cold-war alliance Nato secretary-general Anders Fogh Rasmussen made the implied threat during a visit to Ukraine.