Four servicemen were killed in an attack by members of illegal armed groups in the vicinity of Luhansk on June 17, Ukrainian National Security and Defense Council Secretary Andriy Parubiy said.

"Ukrainian military attacked Russian militants in the vicinity of Luhansk. There are significant losses among the invaders, but there are also casualties among our soldiers Four servicemen of the legendary 24th Aidar territorial defense battalion comprising Maidan self-defense fighters died in that battle," Parubiy wrote on Facebook early on Wednesday.