Three Ukrainian soldiers have been killed and four others injured in fresh clashes between pro-Russian separatists and Kiev forces in Ukraine’s war-scarred east, the military said Sunday.

Three Ukrainian soldiers have been killed and four others injured in fresh clashes between pro-Russian separatists and Kiev forces in Ukraine's war-scarred east, the military said Sunday.

"In the past 24 hours, as a result of intense fighting, three Ukrainian soldiers were killed and four were injured," Ukrainian military spokesman Andriy Lysenko told journalists.

Lysenko said the servicemen had died as a result of an explosion and shelling in the town of Krymske, some 40 kilometers northwest of the rebel stronghold of Lugansk.

"Illegal armed groups fired throughout the front line," he said. "There were no quiet areas."

On Saturday, the leader of a self-proclaimed separatist republic in eastern Ukraine was injured in a suspected car bombing Kiev said was likely linked to an internal power struggle among rebel leaders.

Igor Plotnitsky, the head of the Lugansk People's Republic, did not sustain life-threatening injuries in the blast, local media reported.

Lugansk is the smaller of two breakaway pro-Russian provinces that have been fighting Ukrainian government forces for more than two years.

Fighting in the region has surged in recent weeks, with Kiev reporting increasing numbers of military casualties despite a ceasefire agreement aimed at halting the 27-month conflict.

The Organization for Security and Cooperation in Europe (OSCE) last month urged both separatists and government forces to avoid a return to "large-scale military operations."