Explosions in east Ukraine threaten ceasefire

Powerful explosions in a key frontline city in eastern Ukraine on Saturday raised fears that a day-old truce between government and rebel forces had already collapsed. Numerous explosions were heard and thick smoke was visible on the horizon of Mariupol, a government-held port city in the east of the country. A checkpoint held by Ukraine loyalists seemed to be on fire late on Saturday, according to AFP journalists close to the scene. The renewed violence came just hours after a phone call between Ukraine's President Petro Poroshenko and his Russian counterpart Vladimir Putin, who agreed that a ceasefire signed on Friday "was generally being observed".