Heavy shelling rocks rebel-held Donetsk in east Ukraine

Military trucks are seen through a car window as they drive along a road on the territory controlled by the self-proclaimed Donetsk People's Republic in Makiivka (Makeyevka) in Donetsk region, eastern Ukraine, November 11, 2014. REUTERS/Maxim Zmeyev

DONETSK Ukraine (Reuters) - Fresh volleys of artillery fire were heard across many parts of the separatist stronghold of Donetsk in eastern Ukraine on Sunday, a Ukrainian government statement said, after Kiev warned again of rebel preparations for a fresh offensive.

A Reuters witness in central Donetsk heard several dozen blasts of artillery fire, although it was unclear who had launched them or what was under attack.