Fighting is continuing on the outskirts of the rebel stronghold of Donetsk in eastern Ukraine despite an agreement reached by the Ukrainian and Russian foreign ministers.

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

Fighting in the east had largely subsided following a ceasefire signed in February but has rekindled in recent days.

Heavy shelling was heard in Donetsk overnight. 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 ceasefire was signed.

Mr 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 yesterday to call for the pullback of smaller-calibre weapons from the front lines.

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

A Russian journalist was injured when he stepped on a land mine in Shyrokyne during a visit to the village on the Azov Sea that has been the epicentre of recent fighting.

Andrei Lunev, a videojournalist who works for the Zvezda television station, received first aid at the scene and was then taken 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.

Foreign ministers from Ukraine and Russia also agreed to support international monitors and establish four working groups to address the most pressing issues faced by people in the embattled region.

The meeting in Berlin also involved the French and German foreign ministers.

German foreign minister Frank-Walter Steinmeier, who hosted the meeting, insisted afterwards that the parties had no alternative but to abide by agreements forged in the Belarusian capital Minsk in February and September.

"Everyone knows that we have a long path ahead of us," he said. "But we're going to do everything we can to continue this process."

He said the new deal calls for the withdrawal of mortars and heavy weapons below 100mm (3.94in) calibre, as well as all types of tanks.

Mr Steinmeier said the four diplomats also agreed on the need to establish four working groups to address security issues, and the process for holding a local election in rebel-occupied areas.

The groups will also attempt to restart the exchange of prisoners of war, and to improve the dire economic situation in eastern Ukraine.

Russian foreign minister Sergey Lavrov said the parties were unable to agree on Ukraine's demands for the deployment of peacekeepers.

He also criticised laws passed recently by the Ukrainian parliament, which he said were eroding the Minsk deal.

"We underlined the need to fulfil the Minsk agreements in their entirety, not just in the military segment, but also in political, economic and humanitarian spheres," Mr Lavrov said.