DONETSK Ukraine (Reuters) - Heavy shelling resumed around the pro-Russian separatist stronghold of Donetsk in eastern Ukraine on Tuesday, a Reuters witness said.
More than a dozen mortar bombs were heard in the city center, though it was unclear who had launched them or what was under fire. Fighting has often centered around Donetsk airport which is outside the city center.
Heavy shelling of Donetsk at the weekend increased concerns that a ceasefire between the rebels and government forces could crumble.
(Reporting by Anton Zverev, Writing by Thomas Grove, editing by Timothy Heritage)