Ukraine's military said Saturday it has finished withdrawing its weapons from the eastern frontline with pro-Russia rebels, where clashes have erupted in recent days despite a ceasefire.

Ukrainian soldiers withdrew their 82 mm calibre mortars from the villages of Pisky and Opytne near the ruins of Donetsk airport, which was ravaged by intense fighting last year, army spokesman Oleksandr Zavtonov told AFP.

Kiev's withdrawal came after pro-Moscow rebels said they pulled out their light arms from the area on Thursday.

A military convoy transporting mortars could be seen moving away from government positions in Pisky towards an arms depot, an AFP journalist said.

A Ukrainian soldier told AFP that troops near the front now have only firearms left.

"We do not respond to the rebels' provocations or shots. But if we must defend ourselves, we now only have guns, Kalashnikov (rifles) and stones," said 39-year-old Eduard, a soldier in Ukraine's 93rd Brigade.

Saturday's pullout completed the government's weapons withdrawal from the Donetsk area and was in line with a trust-building September 1 pact that ordered the withdrawal of all weapons with a calibre under 100 mm.

While the deal led to a marked de-escalation in one of Europe's deadliest crises since the Balkans wars of the 1990s, it remains unclear whether this semblance of calm will last.

The plan is to create a 30-40 kilometre (18-25 mile) buffer zone in the conflict. A similar withdrawal took place in the separatist Lugansk area in October.

A peace deal signed in February in Minsk calls for a vote to be held in the separatist regions under international auspices. Those elections have now been pushed back to early 2016.

Both the government and the rebels say they have honoured a pullout deal regarding larger weapons.

But the Organization for Security and Cooperation in Europe (OSCE), tasked with overseeing the withdrawal, has said some heavy weapons remain deployed on both sides of the frontline.

- 'Volatile' -

Chief OSCE monitor Ertugrul Apakan said this week that the ceasefire was "largely holding" but that the situation remains "volatile".

On Saturday the government and the separatist rebels exchanged blame over continued violence.

Kiev accused the rebels of firing at their positions using guns, grenade launchers and mortars. Four soldiers were wounded after they stepped on a landmine, the government added.

The rebels meanwhile accused Kiev loyalists of pounding Donetsk with a rocket launcher.

"Ukrainian volunteer battalions are bombing Donetsk in order to derail the Minsk (peace) agreement and to provoke a response from us," the separatists' defence ministry spokesman Eduard Bassurin said.

The conflict, which erupted in the aftermath of 2014's pro-democracy revolt, has left more than 8,000 people dead.

Russia denies instigating and backing the revolt in reprisal for last year's ouster of a Moscow-backed president in Ukraine and the subsequent leadership's decision to tie its future to the European Union and the NATO military bloc.