Ukraine's army on Wednesday accused pro-Russian forces of launching a new attack against its positions in breach of a brittle ceasefire, with at least one civilian killed and several others wounded in the fresh clashes.

Fighting has intensified around key hotspots on the frontline in eastern Ukraine and the latest violence revived fears that pro-Russian separatists may be readying for a new advance against Kiev forces.

Rebel forces began a "large-scale offensive against Ukrainian positions" close to the separatist stronghold of Donetsk at 4 am (0100 GMT) using about a dozen tanks and up to 1,000 troops, said Ukraine's General Staff.

Government troops had fought back against the attack using heavy artillery, it added in a statement.

Senior rebel commander Eduard Basurin confirmed that fresh fighting had taken place around Maryinka, a settlement just to the west of Donetsk, but denied that rebel forces had taken control there.

Ukrainian Defence Minister Stepan Poltorak said the rebels had halted their attack at 3 pm (1200 GMT), adding that seven Kiev soldiers had been wounded.

Both sides, citing preliminary information, said eight people -- four rebels and four civilians -- had been killed in total in eastern Ukraine over the past day.

Rebel commander Basurin told AFP that one civilian was killed in Donetsk and four were wounded in the fresh fighting Wednesday.

Separately Volodymyr Kolesnyk, from the Donetsk region's health department which is loyal to Kiev, told AFP that six civilians had been wounded in Maryinka.

An elderly couple also died when their car came under mortar fire in the separatist-held Lugansk region, the regional pro-Kiev governor Gennady Moskal said.

Fears in Kiev have swirled in recent weeks that pro-Moscow rebels may use the relative lull in fighting to regroup and prepare for a new offensive to push deeper into Ukraine-controlled territory.

"We don't know the militants' plans," said Ukrainian military spokesman Andriy Lysenko.

"But we do understand that if such activisation has started then there is a clear signal from Moscow."

Rebels have denied plotting a new offensive.

- Checkpoints closed -

A ceasefire was put in place in February after a deal was reached by the leaders of Russia, Ukraine, France and Germany, but it remains fragile and fighting has rumbled on around key hotspots in the country's east.

On Tuesday, Kiev accused Moscow of sabotaging crisis talks after a meeting in Minsk aimed at advancing the peace agreements was postponed to a later date.

Kiev and the West accuse the Kremlin of supporting and arming the pro-Russian separatists, which Moscow denies.

Ukrainian authorities said the pro-Russian rebels attacked its troop positions near Maryinka with Grad rockets and tanks.

Maryinka and Georgiivka, areas under control of Ukrainian forces about 30 kilometres (19 miles) from Donetsk, came under "intense shooting" from the morning, Vyacheslav Abroskin, chief of the Donetsk region's police, who is loyal to Kiev, told AFP.

A traffic policeman told AFP that all checkpoints to Ukraine from the self-proclaimed Donetsk People's Republic were closed to traffic, with many civilians left stranded because of the shooting.

"We went to Mariupol to buy some food," Inna, who lives near Donetsk, told AFP at one of the checkpoints.

"We've been standing in the sun for several hours now, the military says there are a lot of unexploded shells farther down the road."

The conflict between the Ukrainian army and insurgent forces has killed more than 6,400 people since fighting first erupted in April 2014.
Source: AFP