"They (the separatists) are using automatic weapons, snipers and grenade launchers against the battalion," Semen Semenchenko, the commander of a pro-Ukrainian militia group called the Donbass region battalion, said on his Facebook page.
Yuri Bereza, the commander of pro-Ukrainian self-defence forces in a nearby region who had headed to the scene, told Reuters by telephone: "The fighting is still going on, we are evacuating the wounded." He gave no figure for the wounded.
On Thursday, at least 13 Ukrainian servicemen were killed in a firefight with rebel gunmen south of Donetsk, an industrial hub where the separatists have proclaimed a 'people's republic' and have vowed to disrupt Sunday's presidential election, Reuters reported.