In the past 24 hours illegal armed formations have attacked counter-terrorism operation forces 16 times and six Ukrainian law enforcers were killed, Ukrainian National Security and Defense Council information and analytical center spokesman Andriy Lysenko said at a briefing on Tuesday.

"In the past 24 hours illegal armed formations fired at Ukrainian armed forces' subdivisions posts and positions 16 times near the settlements of Krasnotalivka, Cheremshyne, Oleksandrivka, Zemlyane, Stukalova Balka, Shyshkove, Amvrosiyivka, Sverdlovsk, Nyzhnioderevychka, and Stepanivka," Lysenko said.

In response, counter-terrorism operation forces opened fire at militants' positions, he said.

During clashes in the past 24 hours six Ukrainian servicemen were killed and 13 were injured, Lysenko said. All people injured have been brought to hospitals and provided with relevant medical care, he said.

Meanwhile, militants and Russian mercenaries are still attempting to redeploy automobile and armored weapons and are firing in the vicinity of the frontier subdivisions, Lysenko said.

In past 24 hours Krasna Talivka Luhansk border service detachments have been fired on from automatic weapons from Russian territory.