LUHANSKE, Ukraine -- Russia-backed rebels in eastern Ukraine claimed Tuesday to have taken the key transportation hub of Debaltseve as both parties faced a deadline to start pulling back heavy weapons from the front line.
Fierce fighting on Tuesday appeared to be focused on Debaltseve, a government-held town surrounded by rebel forces that both sides claim to be on their side of the cease-fire line. The issue was not resolved under a cease-fire agreement negotiated last week by the leaders of Ukraine, Russia, Germany and France.
Separatist leaders said in remarks carried by the rebel mouthpiece Donetsk News Agency on Tuesday afternoon that their forces have pushed the Ukrainian army out of Debaltseve, gaining control over most of the town.
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 cease-fire being fully observed. He said at least five troops were killed and nine injured in the past 24 hours in the war zone.
The cease-fire 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.
The war in eastern Ukraine has already killed more than 5,600 people and displaced more than a million, according to U.N. figures issued Monday. It has also left the country's industrial heartland in ruins.
Fighting has stopped or subsided in some parts of war-torn eastern Ukraine, however. Rebel military spokesman Eduard Basurin said Tuesday they separatists had not seen any violations of the cease-fire in the area around the rebel stronghold of Donetsk since 8 p.m. Monday.
Rupert Colville, spokesman for the U.N. 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 Luh tenuous, Ukraine rebels claim ansk 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."
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 cease-fire, the Organization for Security and Cooperation 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.