At least three Ukrainian soldiers were killed and four other wounded in an intensified offensive carried out by independence-seeking insurgents on Thursday afternoon in eastern Ukraine, a military spokesman said.
Vladislav Seleznev, the spokesman for Ukrainian army, said that most of the casualties occurred in an assault on the government- controlled airport in Donetsk where rebel forces used mortars to try to push Ukrainian troops out of the airport building.
Seleznev blamed the rebels for the continued violence, saying that the Ukrainian forces open fire only in response.
Meanwhile, the rebel army accused the government troops of violating the truce agreement 18 times over the past 24 hours and said that one of its fighters was wounded in the battles.
On the whole, the confronting sides in eastern Ukraine exchanged fire 26 times in the past day, the press service of the Ukrainian forces said.
The armed conflict in eastern Ukraine, which rages since mid- April, has claimed at least 4,000 lives and wounded more than 9, 300 others.
Both sides have repeatedly accused the other of initiating battles and violating a truce deal that came into force in early September.