The guns have been mostly silent since early September, but there has been an increase in ceasefire violations over the past few weeks, with both sides blaming the other for the escalating violence.
"This is the highest death toll within the past two months. All losses are related to the combat clashes with sabotage groups," Ukrainian military spokesman Andriy Lysenko said.
Another four soldiers were wounded, Lysenko added.
Separatist officials said on Saturday Ukrainian troops had fired tanks and mortars near Donetsk airport and the city of Horlivka, rebel news agency DAN reported.
Under the ceasefire deal, both sides are meant to have withdrawn most weapons from the frontline as part of a 12-point peace plan designed to end a conflict that has killed over 8,000 people since April 2014.
Ukraine has repeatedly asked Western nations to provide Kiev with modern weapons while the United States and other NATO countries say the aid they issued to Kiev could not include lethal weapons requested by Ukraine.
On Saturday, Ukrainian armed forces received two U.S.-made TPQ-36 weapon-locating radars, designed to detect and track incoming artillery and rocket fire to determine the point of origin for counterbattery fire.
"This is what we need as air. It will become an effective deterrent to aggressors," Ukrainian President Petro Poroshenko said during a trip to Lviv in western Ukraine.
Earlier this year Ukraine received counter-mortar radar systems.
Non-lethal aid also included body armor, helmets, vehicles, night and thermal vision devices, heavy engineering equipment, advanced radios, rations, tents.
Source: Google News