KIEV: Interfax-Ukraina news agency is citing a Ukrainian Interior Ministry official as saying at least 30 servicemen were killed after pro-Russian rebels fired missiles at them early Friday.
Zoryan Shkiryak, an adviser to the Interior Minister, was quoted as saying authorities would react swiftly to the attack.
Ukrainian government troops have been mired in fighting for more than three months with a rebel army seeking secession for eastern regions of Ukraine.
Rocket attacks on army encampments and checkpoints have become an almost daily occurrence and the death toll among troops has been steadily mounting.
Government forces had appeared to turn the tide last weekend, however, when they forced rebels out of their stronghold in the city of Slovyansk.