Intense fighting continued near two cities in eastern Ukraine on Friday, raising further doubts about whether the ceasefire deal agreed in Minsk has any chance of success.

According to the Minsk plan the ceasefire will start on Sunday but, rather than abating, the conflictappeared to escalate on Friday. The Ukrainian defence ministry said pro-Russia forces were trying to take the cities of Debaltseve and Mariupol before the truce begins. On Friday afternoon, the Guardian witnessed incoming and outgoing heavy weapons fire on the contested highway leading to Debaltseve, which was lined with burned-out trucks.



A spokesman for the Ukrainian military said 11 soldiers had been killed and 40 wounded in 24 hours and there were reports of numerous civilians being killed.



The increase in violence took place as it emerged that the Russian president, Vladimir Putin, sought to delay agreement on a Ukrainian ceasefire at talks in Minsk because he wanted pro-Russia separatists to capture the railway hub in Debaltseve.



Three of the four leaders at the talks in Minsk – the German chancellor, Angela Merkel; France’s president, François Hollande; and Ukraine’s embattled president, Petro Poroshenko – dashed to the Brussels summit from Belarus.



Briefing 26 EU heads of government on the fraught negotiations that resulted in a truce that was supposed to start on Sunday, the Minsk participants painted a picture that failed to inspire confidence.



Witnesses to the discussion said all the EU leaders were sceptical about the success of the Minsk peace plan, not least because Putin had resisted pressure for a ceasefire. He hoped to delay the truce by 10 days, the summit heard, in order to force the surrender of up to 8,000 Ukrainian troops who are surrounded in Debaltseve by pro-Russia separatists.



Putin was said to have made it clear that Debaltseve had to fall. The Russian president has also said publicly that the separatists had the Ukrainian forces encircled and that “of course, they expect [the Ukrainians] to lay down their arms and cease resistance”.



While the 13-point peace plan is complex and relies upon political developments at least a year away, Poroshenko’s priority was to get a ceasefire. The Ukrainian leader delivered an emotional report to the summit on the plight of eastern Ukraine, witnesses said. He said he had not slept for two nights. Before the Minsk talks, he went to a hospital in the eastern town of Kramatorsk, where he was deeply affected by the sight of a four-year-old boy who had lost limbs in a shelling by separatist forces.



On the Ukraine deal, the mood of the EU summit was sombre, with the leaders concluding that Putin was more interested in war than in peace.



On Friday, Poroshenko was similarly pessimistic. “I don’t want anyone to have any illusions and so I am not seen as a naive person: we are still a very long way from peace,” he said during a visit to a military training ground. “Nobody has a strong belief that the peace conditions which were signed in Minsk will be implemented strictly.”

Gernot Erler, an adviser to Merkel on Russia, warned on Friday of the “threat that in the last hours before the ceasefire, the two sides will try to increase the others’ losses”. That was what appeared to be happening near Debaltseve, where Ukrainian soldiers told the Guardian that they had been under heavy shelling for two days but had seen “intensified fighting” on Friday. Rebels have been redoubling their weeks-long effort to tighten the noose around the town and its key railway junction.



The general staff denied that its troops in Debaltseve were surrounded but the situation on the ground suggested the government forces’ situation was more complicated than that.



Burned-out trucks – some still smoking – lined the cratered highway from Artemivsk to Debaltseve, which remains in contention. Government soldiers who were trying to tow a damaged ambulance out of the partly ruined town of Luhanske admitted that anyone who went further down the highway towards Debaltseve would come under heavy fire from rebel small arms and artillery.



“We control the highway, but it’s being shot up,” said a soldier with the call sign Thunderstorm. As he spoke, incoming artillery rounds whistled nearby, and Ukrainian forces began answering with mortar fire.



Putin’s spokesman, Dmitry Peskov, said on Friday that there was a “danger” that Ukrainian forces in Debaltseve would continue try to break out of the alleged encirclement and in doing so violate the ceasefire once it takes effect.



According to the Ukrainian military, rebels had used rockets and artillery to attack government forces in Debaltseve on Friday. It said its forces were firing back only when attacked.



But far back from the frontlines, government forces were firing heavy weapons on Friday afternoon near Artemivsk, increasing their intensity towards dusk. The Guardian also saw a stream of smoke that appeared to be from outgoing rocket fire near Ukrainian positions in Mironivsky.



In the small town of Svitlodarsk near Ukrainian positions, residents repaired damage done to their homes from shelling as outgoing fire boomed, only running for cover when the deafening whine of incoming rockets and mortars began overhead.



Anna, a shopkeeper, said she didn’t believe that the ceasefire due to start on Sunday would work. “I’m just a simple merchant, but it doesn’t seem realistic. Why have they been bringing so much weaponry to this area?” she said as she cleaned up debris in her shop, which was struck by a shell on Monday.



Asked about the ceasefire agreed in Minsk, Thunderstorm broke out laughing. “The ceasefire is a fiction for the west,” he said.



In another ominous note for the ceasefire, Dmytro Yarosh, leader of Right Sector, a Ukrainian nationalist fighting group, said on Friday that any agreement with “pro-Russia terrorists” was “unconstitutional” and that his unit “reserves the right to continue active military operations”.



Fighting also continued on a second front near the coastal city of Mariupol. The Azov volunteer battalion said it was engaged in a “tank battle” with pro-Russia forces for control of the village of Shirokine and “artillery duels” for the village of Sakhanka. Ukrainian forces have been fighting rebels along the Azov coast this week in what Poroshenko said was a counter-offensive to push the frontline back to where it was before the ceasefire deal agreed in September.



Both sides in the conflict accused each other of killing civilians on Friday morning. Regional authorities said pro-Russia forces had shelled the government-held town of Gornyak, near Donetsk with Grad rockets, killing four people and injuring 16.

Two people were also killed and six wounded when a shell hit a packed cafe in the Kiev-controlled town of Shchastya near rebel-held Luhansk, a local official said, adding that other shells had struck elsewhere in the town.



The rebels accused Ukrainian forces of shelling the separatist stronghold of Donetsk and the town of Horlivka, where they said three children had been killed. It was not possible to verify either of these reports, though an AFP journalist in Donetsk said that sporadic missile salvoes and dozens of artillery bombardments could be heard from the city starting early on Friday morning.



The ceasefire agreed in Minsk was intended to pave the way for a comprehensive political settlement and followed a fraught 16 hours of overnight negotiations.



The summit resulted in a pact providing for a ceasefire between Ukrainian government troops and Russian-backed separatists, a withdrawal of heavy weaponry from the battle zone that is to be demilitarised, amnesties on both sides, and exchanges of prisoners and hostages.



The ceasefire and weapons pullback is to be monitored by the Organisation for Security and Cooperation in Europe (OSCE). “The next 48 hours will be crucial,” said one EU diplomat at the Brussels summit.

Merkel cautioned against over-optimism and was guarded about whether the peace pact would be implemented. “We have a glimmer of hope … but no illusions,” she said.



Depending on how events play out in eastern Ukraine, EU leaders are expected to decide whether to reinforce or relax economic sanctions on Russia next month.



US officials also said they were not taking sanctions off the table and bluntly warned the separatists against seizing more land before Sunday’s ceasefire takes effect.



David Cameron, the British prime minster, likewise urged EU leaders to stand firm on maintaining sanctions against Russia, saying it was “actions on the ground rather than just words on a piece of paper” that mattered.

