Rebels close in on government soldiers, trapped in ruins and running out of food and supplies after more than a week under siege

Pro-Russia forces seized parts of the strategic railway hub of Debaltseve in intense street fighting, ignoring a shaky ceasefire agreement, as a deadline for removing heavy weapons from the frontlines went unheeded.

The rest of the conflict zone appeared calm on Tuesday, three days after a halt in hostilities, negotiated by Russian, Ukrainian, French and German leaders, came into effect. But in Kiev, a senior official warned that “the hopes of the world for peace are being destroyed”.

Rebels who claimed a moral imperative to fight for the town closed in on government soldiers, trapped in bombed-out ruins and running out of food and supplies after more than a week under siege.

Separatist troops have been shelling any government forces that tried to move in or out from the main Ukrainian lines 10 miles away.

The size of Debaltseve – it was home to around 25,000 people before the war emptied its streets – belies its importance to rebels as the site of a rail junction connecting their strongholds of Donetsk and Luhansk.

Vladimir Putin sought to delay the ceasefire by 10 days because he wanted to give separatists time to capture the town, an EU summit was told last week.

Now leaders of pro-Russia forces appear to be gambling that the ceasefire can wait while they battle for Debaltseve, and have effectively put the provisions of the deal on hold.

The rebels have been trying to take the town for weeks, and on Tuesday Kiev’s forces appeared to be losing their grip on the bombed-out remains of its streets, and the crucial train junction.

“The railway station is partially under the control of the terrorist fighters,” said Ilya Kiva, deputy head of the Donetsk regional police. “Active fighting is going on inside the city, there’s essentially a struggle for every block and every street,” he told television channel 112 Ukraine.

He denied reports that the police station had also fallen, including one from journalist Andrei Tsaplienk who said he was on the ground and posted updates about the situation on Facebook.

“The police station is under the control of the Ukrainian security services,” Kiva said. “The situation could change any minute or any hour, because we have orders to observe the ceasefire, and all we can do is try to defend our positions in response, and we can’t start to act with full force.”

When reached by the Guardian on Tuesday, Kiva confirmed he was in Debaltseve but refused to speak further because of the critical situation.

Putin told Kiev to let its soldiers surrender to pro-Russian rebels. “I hope that the responsible figures in the Ukrainian leadership will not hinder soldiers in the Ukrainian army from putting down their weapons,” the Russian president said.

“If they aren’t capable of taking that decision themselves and giving that order, then (I hope) that they won’t prosecute people who want to save their lives and the lives of others.”

He added that he hoped the rebels would allow the Ukrainians to return to their families, once they had surrendered the town.

Albert Sardaryen, a Ukrainian national guard medic in Debaltseve, told the Guardian that he had been trapped in the city since 5 Feb, when he turned up for a 12-hour shift and wasn’t able to leave. The dead and injured are not allowed out, he said.

Pro-Russia forces are already in parts of the city and Sardaryen’s unit had exchanged close-quarters machine gun fire with rebels on Tuesday, he said, cutting the conversation short when mortar fire began landing nearby.

The original ceasefire had lasted less than an hour, he said. “It was heavy shelling all day long and then at midnight it became silent. We were surprised thinking it could be a real truce, but before 1am it all resumed,” he told the Guardian by phone from inside the ruined city.

Despite the calm elsewhere, the violence in Debaltseve could damage the wider ceasefire, Ukranian officials warned. The situation was heading towards “further escalation”, the AFP quoted Valeriy Chaly, deputy head of the presidential administration, as saying at a news conference.

Both sides say they cannot move their heavy weapons back from the frontline while attacks are still underway. “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,” Denis Pushilin said.

Berlin said on Tuesday that both sides had agreed concrete measures to allow international observers, from the Organisation for Security and Co-operation in Europe, to monitor the ceasefire. They have not yet been able to access Debaltseve.

Laurent Fabius, the French foreign inister, warned on Tuesday that key components of the deal he helped negotiate were not being followed, despite an overall reduction in fighting, AFP reported.

“We can say the ceasefire is being generally respected, but there are two major ‘buts’,” Fabius told the French parliament, naming the fighting around Debaltseve and the failure to withdraw heavy weapons from the frontline. “Clearly, these two aspects are fundamental.”

In an indication of the progress rebel forces have made, Alexander Zakharchenko, head of the self-declared Donetsk People’s Republic, gave an interview to LifeNews on the city’s outskirts on Tuesday in which he said the town would be “cleansed of the enemy” within three days.

“We’re located in Debaltseve itself,” Zakharchenko said. “Coal from the DPR will go to Luhansk and other cities through this railroad junction,” he said, before he took a wound to the ankle and was evacuated from the town. The injury was not serious, LifeNews said. “The head of the DPR was conscious while being transported and feels excellent,” it said.

Kiev denies that its troops in Debaltseve are cut off, even though the national guard medical chief in Artemivsk told the Guardian that the last time his men had been able to evacuate injured soldiers was on Thursday. “We took 22 wounded men out through the fields,” he said. “The road has been impassable since Monday.”

Human rights organisation Euromaidan SOS, which has been a key source of information since the protests that toppled the government last winter, reported after speaking to soldiers inside Debaltseve on Tuesday that the “encirclement has become a reality”.

Rebels have surrounded Ukranian soldiers in villages just outside the town, the group said on its Facebook page, suggesting the pro-Russia forces are trying to separate Kiev’s troops into ever smaller and more vulnerable pockets.