Over the past two months, government troops have fought back, gaining ground against the rebels, who are led almost exclusively by Russian citizens and have managed to acquire tanks, missiles and other heavy weaponry that Kiev and its Western allies say can only have come from across the frontier.
Kiev said 18 Ukrainian servicemen had been killed and 54 injured in 25 separate clashes over the past day ineastern Ukraine. Military spokesman Andriy Lysenko said troops had been shelled from inside Russian territory and frontier guards had come under a four-hour mortar and artillery attack.
Fighting has intensified since Malaysia Airlines flight MH17 crashed on July 17, killing all 298 people on board. Western countries say it was shot down by rebels with an advanced anti-aircraft missile supplied by Russia.Moscow denies blame, and the Russians who command the rebels deny they had such missiles.