Fighting raged overnight and in the early hours on Tuesday on the outskirts of the rebel stronghold of Donetsk in eastern Ukraine despite an agreement reached by the Ukrainian and Russian foreign ministers a day earlier.

The yearlong military conflict between Russian-backed rebels and government forces has claimed more than 6,000 lives and left large parts of Ukraine's once industrial heartland in ruins.

Fighting in the east had largely subsided following a cease-fire deal signed in February but has rekindled in recent days.

Heavy shelling was heard in Donetsk late Monday evening and in the early hours on Tuesday. In the morning, rebel mouthpiece Donetsk News Agency reported one rebel fighter dead and five wounded in the overnight clashes.

Russia and Ukraine agreed in Berlin on Monday to call for the pullback of smaller-caliber weapons from the front lines of the conflict that has claimed more than 6,000 lives.

German Foreign Minister Frank-Walter Steinmeier, who hosted the talks in Berlin, said the new deal calls for the withdrawal of mortars and heavy weapons below 100 mm (3.94 inches) caliber, as well as all types of tanks.

On the ground, however, even the previous agreement that called for a cease-fire and a withdrawal of large-caliber weaponry appeared to be shaky.

Fighting appears to be focused on the now-obliterated Donetsk airport and the village of Shyrokyne by the Azov Sea in the south.

An Associated Press reporter saw a column of at least 10 infantry combat vehicles moving Tuesday morning from the rebel-occupied area by the Azov Sea to Donetsk.