Russia has said military action by the Ukrainian government would prompt an "inevitable further escalation of the conflict" with pro-Russian separatists in eastern Ukraine and undermine any peacemaking.

Russia has stepped up criticism of Kiev since violence has intensified in the conflict, where a fragile ceasefire signed in September collapsed after rebels drove Ukrainian government forces out of the strategically important Donetsk airport.

A rebel advance launched last week appears to have buried the truce. The separatists say their initial objective is to drive back government forces out of artillery range of the cities they hold and improve their grip on key strongholds.

"The latest military actions provoked by Kiev will lead to the inevitable further escalation of the conflict (and) undermine efforts taken by the international community to end the bloodshed," Russia's Foreign Ministry said in a statement.

The US and the EU accuse Russia of arming and funding the rebels. With the latest outbreak of fighting, the EU has prepared a draft for its sanctions against Moscow to be extended by six months and expanding the number of targets. Russia denies sending soldiers or arms to the separatists in Ukraine's Donetsk and Luhansk areas.

The Russian Foreign Ministry said yesterday there had been 68 cases of shelling of civilian areas in the last day, including mortar bombs it said were fired by Ukrainian government forces at the rebel-held city of Luhansk and its surroundings.

Fighting over the last nine months has killed 5,000 people and caused more than a million people to flee.