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. Ukrainian military spokesman Andriy Lysenko told a televised briefing that six troops were killed and 12 wounded in a 24-hour period, while rebels reported one fighter dead and five wounded in the overnight clashes.

The death toll is the highest since the February cease-fire was signed.

Lysenko also reported civilian casualties, including two teenagers who were wounded in shelling in the Horlivka area, north of Donetsk.

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.

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.

A Russian journalist was injured Tuesday morning when he stepped on a land mine in Shyrokyne during a visit to the village on the Azov Sea that has been the epicenter of recent fighting. Andrei Lunev, a videojournalist who works for the Zvezda television station, received first aid at the scene and was then whisked away to the nearest hospital. At one point during the visit the group had to lie on the ground because of an exchange of fire nearby.

Shyrokyne has changed hands repeatedly throughout the conflict.

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.