KIEV (Reuters) - Three civilians and two Ukrainian soldiers have been killed in eastern Ukraine, renewing pressure on Thursday on a four-month truce in the separatist conflict, and international monitors said violence could surge at any moment.
The two Ukrainian soldiers were killed and 13 others wounded by separatists using heavy weapons in violation of a ceasefire agreed in February, a military spokesman said in Kiev.
The three civilians were killed on Wednesday night in a mortar attack near Gorlivka, which is in separatist-held territory north of the regional city of Donetsk. The military and the rebels blamed each other for the attack.
A ceasefire between the two sides brokered in February by the leaders of Ukraine, Russia, Germany and France has stemmed large-scale fighting though regular skirmishes near Donetsk are claiming lives almost daily on both sides.
A spokesman for the Organization for Security and Cooperation in Europe spokesman, Michael Bociurkiw, said the situation had stabilized following serious fighting between government forces and separatists at Maryinka, 23 km (14 miles) west of Donetsk on June 3, which shook the tenuous truce.
But he said re-location of personnel and weapons in the area meant "the normal pattern of violence has re-asserted itself ... the threat of a sudden flare-up still remains".
Areas in and around Donetsk airport, which fell to the rebels in January, remained the primary focus of fighting with 331 explosions recorded on June 9, he said.
Despite claims to the contrary, neither side has completed the withdrawal of heavy weapons as agreed in the four-power talks last February in Minsk, Belarus, Bociurkiw said.
The Minsk deal is held by all sides as the basis for reaching a peace settlement in a conflict which erupted in April, 2014, after Russia annexed Crimea and which has cost more than 6,400 lives according to U.N. figures.
But the United States, its Western allies and Kiev accuse Russia of failing to implement the Minsk agreement by keeping its troops in Ukraine and arming the rebels.
Moscow, which denies direct involvement in the conflict, takes the side of the separatists in accusing Ukrainian forces of attacking rebel positions in urban areas, in violation of the agreement.
U.S. Ambassador to the United Nations, Samantha Power, visiting Kiev on Thursday, said the United States remained supportive of the Minsk agreement despite violations. Most had been carried out by separatists and by the re-appearance on the field of heavy weapons which had previously been withdrawn, she said.
"There's a political solution, diplomatic pressure to try to ensure better implementation in the near term and full implementation ultimately and that is the necessary course even if, right now, it's a halting one," she said.
Power said Western sanctions against Russia over the Ukraine crisis had a devastating effect on the Russian economy. She said that while these had not immediately forced Russia to withdraw its forces and weapons from Ukraine, Russia would feel the effect of being isolated over time.
(Writing By Richard Balmforth; Editing by Angus MacSwan)