Soldiers from the Ukrainian self-defence battalion "Azov" check vehicles at a checkpoint in the southern coastal town of Mariupol September 8, 2014. Ukrainian forces said on Monday they had come under sporadic fire overnight from pro-Russian separatists in eastern Ukraine, but Reuters witnesses said overall a ceasefire agreed between the two sides appeared to be holding. A Reuters reporter heard a short blast of artillery fire early on Monday to the east of Mariupol, a port on the Sea of Azov near the Russian border which saw heavy fighting before Friday evening's ceasefire. Both the rebels and the Ukrainian military insist they are strictly observing the ceasefire and blame their opponents for any violations. REUTERS/Vasily Fedosenko (UKRAINE - Tags: CIVIL UNREST POLITICS MILITARY)