A Ukrainian soldier has been killed and two wounded in restive eastern regions despite a cease-fire deal with separatist rebels.
The truce has been largely holding since the start of September, allowing the two sides to extend a pullback of weapons.
Ukrainian Defense Minister Stepan Poltorak said the attack took place on October 13 when separatists fired grenade launchers at Ukrainian forces near Avdiyivka, a government-controlled town just north of the rebel-controlled city of Donetsk.
Poltorak said details were still sketchy and suggested a rogue group not controlled by rebel leaders could be behind the attack.
The withdrawal of weapons from the front line was agreed on condition that both sides fully respect the cease-fire.
Fighting between Ukrainian government forces and the separatists in Ukraine's eastern Donetsk and Luhansk regions has killed more than 7,900 people since April 2014.