Despite a 72-hour cease-fire extension announced by Ukraine President, Petro Poroshenko,sporadic fighting continues in Donetsk and Luhansk in the east of the country.
Ukranian troops regained control of a key checkpoint in Donetsk after it came under attack from pro-Russian separatists on Thursday night.
The Ukrainian Defence Ministry says four soldiers were killed and five wounded.
Pro-Moscow fighters have also taken over of a Ukrainian National Guard base in Donetsk.
The separatists released the guardsmen, but the base commander is being held.
Poroshenko announced the cease-fire extension after signing a far-reaching trade pact with the EU in Brussels.
The newly elected president said the government reserves the right to terminate the cease-fire in areas where rebels violate the truce.