Heavy shelling rocked the outskirts of the pro-Russian rebel stronghold of Donetsk in eastern Ukraine on Monday, one day after Ukraine held a parliamentary election, the city mayor's office and officials in Kiev said, according to Reuters. "Powerful firing has been heard from high-calibre guns and explosions," the Donetsk mayor's website said. Despite a Sept. 5 ceasefire between Kiev and pro-Russian separatists in the east, tensions remain high.