At least three soldiers were killed and 14 wounded in violent clashes with independence-seeking insurgents in eastern Ukraine over the past 24 hours, a military spokesman said Monday.
Andrei Lysenko, spokesman for Ukraine's National Security and Defence Council, said that the upsurge in violence was reported around the cities of Lugansk and Donetsk.
"The fiercest fighting was raging in the Donetsk airport. For the third consecutive day, the militants were carrying out unsuccessful attempts to conquer this strategic facility," Xinhua quoted Lysenko as saying.
During the battles for the airport, the rebels suffered "serious losses", the spokesman said, without giving details.
A residential neighbourhood of Donetsk also came under heavy shelling overnight, in which 14 civilians were injured, local authorities said.
The shelling destroyed several private houses and public infrastructure, leaving thousands of Donetsk residents without electricity and gas, Donetsk city council said in a statement, without specifying who fired the shells.
The armed conflict, which erupted in eastern Ukraine in mid-April, has claimed more than 4,350 lives and injured more than 10,000 others.