Ukrainian government troops and Russia-backed rebels failed to start pulling back heavy weaponry from the frontline in eastern Ukraine on Tuesday as a deadline to do so passed.

Under a ceasefire agreement negotiated by the leaders of Ukraine, Russia, Germany and France last week, the warring sides were to begin withdrawing heavy weapons from the front line on Tuesday.

Anatoliy Stelmakh, a Ukrainian military spokesman, said in televised comments early on Tuesday that the separatists continued to attack their positions overnight and that the pullout hinged on the ceasefire being fully observed.

“As soon as the militants cease fire, the Ukrainian side will begin to withdraw heavy weaponry from the frontline,” he said.

The Russian news agency RIA Novosti quoted rebel leader Andrei Purgin as saying that the separatists plan to discuss the possible withdrawal of the weaponry later on Tuesday with representatives of Ukraine, Russia and the group charged with monitoring the ceasefire, the Organisation for Security and Cooperation in Europe (OSCE).

Kiev on Tuesday reported artillery strikes overnight around the key transportation hub of Debaltseve while the situation in the rest of the conflict zone appeared to be calm.

An Associated Press reporter heard sustained shelling around Debaltseve – where government troops are encircled – on Tuesday morning, some coming from Grad rocket launchers.

A senior rebel representative told Reuters that the separatists cannot “morally” stop fighting for control of the town.

Denis Pushilin also said rebels could not withdraw heavy weaponry, as set out in the deal, unless Ukrainian forces did so as well.

“We do not have the right [to stop fighting for Debaltseve]. It’s even a moral thing. It’s internal territory,” Pushilin said in the rebel stronghold of Donetsk.

“We have to respond to fire, to work on destroying the enemy’s fighting positions.”

Asked about plans to carry out the agreement to withdraw big guns, he said: “We are ready at any time, we have everything ready for a mutual withdrawal. We will not do anything unilaterally – that would make our soldiers targets.”

Berlin announced on Tuesday morning that the leaders of Russia, Germany and Ukraine have agreed on “concrete measures” to allow OSCE observers to monitor the shaky ceasefire.

The measures were agreed during a phonecall between the German chancellor, Angela Merkel, and her Russian and Ukrainian counterparts, Vladimir Putin and Petro Poroshenko, late on Monday, the government spokesman said, without providing details of the agreed steps.

The agreement is aimed at allowing observers from the OSCE to monitor the situation on the groundaround the strategic railway hub of Debaltseve, the statement said. The OCSE has not yet been able to access the town.

Debaltseve has been virtually cut off from the rest of the Ukrainian forces. A group of Ukrainian soldiers who broke out of Debaltseve on Sunday told the Guardian their column of seven trucks had come under heavy fire from rebel positions despite the ceasefire, and two of the vehicles were destroyed. They said that more than 60% of the city had been ruined by near-constant fires and shelling, and Kiev’s troops are trapped there with dwindling ammunition and supplies.



Ambulance drivers who have been trying to make it through to Debaltseve said both the highway connecting it to the main Ukrainian lines and the nearby fields have been mined, and rebel guns shoot at any vehicles moving across the 10-mile stretch of no man’s land. It has been impossible to use the highway since 8 February, said Alla Neschadym, a national guard medic whose son Oleg is fighting in Debaltseve.

Since the ceasefire started, Ukrainian forces have also suffered casualties fighting for the town of Shyrokine near Mariupol, where mortar attacks were reported on Monday. Kiev began a counteroffensive last week to push back the demarcation line along the Azov coast near Mariupol. The Azov volunteer battalion said this weekend that tank battles and artillery duels were taking place in the area.