Several Ukrainian government soldiers have been ambushed and taken prisoner in Debaltseve, the Defence Ministry said Tuesday, but it denied rebel claims that they have seized control of the key transportation hub.

The ministry said street fighting continued in Debaltseve, which has been the epicentre of fighting in the past two weeks. It didn't say how many soldiers had been seized in the ambush.

Many people fleeing Debaltseve have ended up in nearby cities, seeking humanitarian aid. At a food bank in Slovyansk, one woman who spoke to CBC News burst into tears describing the horror she left behind.

"It’s hell, she said. "And every day it’s getting worse. So many people dying, people burned alive. Some of them were lying on the street for six days."

"I don’t care whose fault it is. All we want is for the conflict to end," she said.

This woman said 'it's hell' in Debaltseve. She fled to the city of Slovyansk, about 90 kilometres away, and spoke to CBC News at a food bank. (Tracy Seeley/CBC)

The Ukrainian presidential office on Tuesday called on the European Union and NATO to condemn the Russia-backed rebels for violating the ceasefire brokered by European leaders last week, a truce that was supposed to have taken effect on Sunday.

Russian news agencies quoted Valery Chaly, chief of the Ukrainian presidential administration, as saying that Kyiv wants the EU and NATO to "resolutely condemn" the separatists for violating the deals.

CBC News is there

CBC News correspondent Nahlah Ayed is in eastern Ukraine with producer Tracy Seeley and cameraman Richard Devey and sent this report Tuesday from Artymovosk, just northwest of Debaltseve:

At a small medical clinic in Artymovosk, several soldiers standing around the entrance fall quiet as the latest ambulance rolls in from Debaltseve. Out comes a stretcher carrying yet another of their colleagues, just returned from the front line.

These are deeply moving — and difficult — moments for the soldiers. They prevent journalists from filming any of the casualties that come in or out of the clinic. “His mother doesn’t know yet,” says one female soldier.

With thousands of soldiers still holed up inside Debaltseve, many Ukrainians are again concerned the national government is not doing enough to support them. For many, it is a violent echo of the siege of Ukrainian bases in Crimea a year ago. Back then, the government was accused of leaving its soldiers at the mercy of Russian fighters, who forced them either to remain and join them, or leave.

There are rumours that some Ukrainian soldiers have surrendered in Debaltseve, as some did in Crimea. There are also reports they’re being sent text messages urging them to give up. None of that is helping morale.

— Nahlah Ayed

The war in eastern Ukraine has already killed more than 5,600 people and displaced more than a million, the United Nations said on Monday. It has also left the country's industrial heartland in ruins.

The government troops and rebels faced a deadline Tuesday to start pulling back heavy weapons from the front line.

Rebel commander Vladimir Kononov said on Russian television that most of Debaltseve was under their control and urged the Ukrainian troops to surrender.

"Their only choice is to leave behind weaponry, lay down arms and surrender," he said.

An explosion after shelling is seen not far from Debaltseve Tuesday. Government forces and pro-Russian separatists said they would not carry out an agreement to pull back heavy guns, pushing a shaky peace deal closer to collapse. (Gleb Garanich/Reuters)

The announcement by the rebels came after fierce fighting that appeared to be focused on Debaltseve. Both sides in the conflict claim the town is on their side of the ceasefire line. The issue was not resolved under the ceasefire agreement negotiated last week by the leaders of Ukraine, Russia, Germany and France.

Also Tuesday, a deadline passed under the agreement for both sides to begin pulling back weaponry from the front line.

The rebels said they were about to begin withdrawing their big guns on some sections of the front line. A rebel military official, Eduard Basurin, announced in a televised briefing that they "will take the initiative" and begin to pull back heavy weaponry from the front line. He did not provide a time line for this.

The Ukrainian government, however, insisted on a comprehensive ceasefire before pulling back its weaponry.

In New York, Adrian Karatnycky, senior fellow with the Atlantic Council, who recently returned from Ukraine, said the value of Debaltseve is in connecting the cities of Luhansk and Donetsk, which "would allow the rebels to have a fully functioning rail and transport system."

We're dealing with more than a battle from East and West. We're dealing with a battle for the heart and soul of Russia. — Adrian Karatnycky

Speaking to CBC News, he said the events in Ukraine are less a fight between East and West than a change in Russian values and whether it respects established borders of sovereign states.

"The interesting thing is that for many years, Russia complied with these kinds of values," Karatnycky said.

"[Russian President Vladimir] Putin is walking away from the kind of positions that his predecessor Boris Yeltsin had, and which he, in effect, honoured until — with regard to Ukraine, at least — until he took over Crimea last winter."

Karatnycky added: "We're dealing with more than a battle from East and West. We're dealing with a battle for the heart and soul of Russia, which has now departed from the rules of engagement, the civilized rules that have kept the peace … since the Second World War."

Sustained shelling

Associated Press reporters saw artillery rounds fired Tuesday from Ukrainian government positions at rebel positions around Debaltseve. Sustained shelling was heard in the area all morning, some coming from Grad rocket launchers.

Ukrainian military spokesman Andriy Lysenko told reporters Tuesday that the separatists continued to attack government positions overnight around Debaltseve and that the pullout hinged on the ceasefire being fully observed. He said at least five troops were killed and nine injured in the past 24 hours in the war zone.

CBC's Nahlah Ayed, located outside the town, said, "We don't know what the fate of all those thousands of Ukrainian soldiers who have been under siege in that town is."

The ceasefire deal, which was brokered by European leaders last week and went into effect early Sunday, specifies the pullout begins on the second day after the parties stop fighting. This condition has not been met, Lysenko said.

"As soon as the fire ceases … we will be ready to begin the withdrawal," he said.

UN alarmed

Fighting has stopped or subsided in some parts of war-torn eastern Ukraine, however. Basurin said Tuesday the separatists had not seen any violations of the ceasefire in the area around the rebel stronghold of Donetsk since 8 p.m. Monday.

Rupert Colville, spokesman for the UN High Commissioner for Human Rights, told a briefing in Geneva on Tuesday that the UN is "alarmed" by reports of continued shelling in the areas and have not yet been able to get reliable information on the casualties there and the wellbeing of civilians.

"It is unclear how many civilians are still there," he said. "We are particularly concerned about the civilians trapped in the area — we believe there may be a few thousand hiding in cellars, struggling to get food, water and other basic necessities."

Elsewhere, at least one rebel leader claimed that his troops had begun to withdraw their heavy weapons.

"I was at the front line last night, and our tanks, our artillery were pulling back," Igor Plotnitsky, the leader of the self-proclaimed Luhansk People's Republic, northeast of Debaltseve, was quoted as saying by the Russian news agency Tass.

He added that he "expects the same from Ukraine."

Talks expected

Due to security issues, his claims could not be immediately verified. Lysenko said the Ukrainian troops "have not noticed any such actions" on the ground.

The separatists were expected to discuss the withdrawal of the weaponry later Tuesday with representatives of Ukraine, Russia and the group charged with monitoring the ceasefire, the Organization for Security and Co-operation in Europe.

In a phone call late on Monday German Chancellor Angela Merkel and Ukrainian President Petro Poroshenko appealed to Russian President Vladimir Putin to use his influence on the separatists to ensure that they stop the fighting.

Merkel's office reported that the three leaders agreed on "concrete steps to enable an observation" of the situation in Debaltseve by the OSCE. It did not elaborate on what these steps would be.

OSCE representatives could not get to Debaltseve on Monday because of the heavy fighting there.