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Vadim Ghirda, Associated Press
Dorina, 3 years-old, leans on a cart used to carry tree branches for fire, outside a damaged apartment building in Debaltseve, Ukraine, Friday, Feb. 20, 2015. After weeks of relentless fighting, the embattled Ukrainian rail hub of Debaltseve fell Wednesday to Russia-backed separatists, who hoisted a flag in triumph over the town. The Ukrainian president confirmed that he had ordered troops to pull out and the rebels reported taking hundreds of soldiers captive.

KIEV, Ukraine — The Ukrainian government and the separatist rebels blamed each other Friday for violating a fragile cease-fire dozens of times, sparking fears of wider hostilities in war-torn eastern Ukraine.

A Ukrainian military spokesman said the Russia-backed rebels fired on Ukrainian positions nearly 50 times in the past 24 hours and that Russia sent more tanks into Ukraine despite a cease-fire that was supposed to begin Sunday.

The rebels, meanwhile, claimed that Ukrainian forces had violated the cease-fire more than 20 times Friday.

The government claims, which followed the rebel seizure of the key rail hub of Debaltseve, raised the question of whether weeks of high-level diplomacy aimed at producing a cease-fire and a peace plan had simply allowed the rebels to redouble efforts to grab more territory.

The village of Kurakhovo, west of the rebel stronghold of Donetsk, was hit by Grad rockets and the village of Berdyansk, near the key port city of Mariupol, was hit overnight by artillery and mortar fire, Lt. Col. Anatoliy Stelmakh, a Ukrainian military spokesman, told reporters.

Russia is still moving military equipment into Ukraine, including 10 tanks brought into Novoazovsk, near Mariupol, he added.

French President Francois Hollande, who brokered the peace deal last week together with German Chancellor Angela Merkel, said Friday he did not have confirmation about Russian tanks entering Ukraine.

"That doesn't mean this doesn't exist," he said, underscoring the need for the cease-fire to take hold and halt the risk of escalation.

Vladislav Seleznyev, a spokesman for Ukraine's military general staff, said two soldiers had been killed in the past day and 110 were being held prisoner by the rebels.

Both sides were supposed to begin drawing back heavy weapons from the front lines Tuesday, but international monitors say they have seen no signs of that.

Concerns are rising that the rebels are still gunning to take Mariupol, a government-held city on the Sea of Azov that could allow them to create a land bridge between Russia and Crimea, which Russia annexed last March. Crimea has no physical link to Russian territory now.

On Thursday, the rebels celebrated their victory over Ukrainian forces in Debaltseve, a key transport hub linking the two largest rebel strongholds in eastern Ukraine. Rebel fighters roamed the town's debris-littered streets, laughing, hugging and posing for photos, although the death of one fighter when his vehicle hit a land mine was a sharp reminder of the dangers that still lurked.

Ukrainian soldiers who made it out of Debaltseve alive on Thursday described weeks of harrowing rebel shelling, followed by a chaotic, hasty retreat. Ukrainian officials said 13 soldiers had been killed and 157 wounded in the fighting, but the shell-shocked soldiers themselves spoke of many more casualties.

"Starting at night, they would fire at us just to stop us from sleeping. They did this all night," a Ukrainian soldier named Andrei said after fleeing Debaltseve. "Then in the morning, they would attack, wave after wave."

The war in eastern Ukraine has killed more than 5,600 people and forced over a million to flee their homes since fighting began in April, a month after Russia annexed Crimea. Russia denies arming the rebels or supplying fighters, but Western nations and NATO point to satellite pictures of Russian military equipment in eastern Ukraine.

In Kiev, nationalists criticized the government for allowing Debaltseve to fall.

Friday was a key anniversary for the months of anti-government protests in 2013-14 that brought down Ukraine's previous, Kremlin-friendly government. A year ago, sniper fire tore through crowds of protesters on Kiev's main square, killing more than 50 people. Dozens more died in earlier clashes with police or were beaten to death under mysterious circumstances.

On Friday evening, President Petro Poroshenko was to be among those honoring them at a memorial ceremony in Kiev.

Hollande and Merkel, who oversaw marathon peace talks last week between the presidents of Russia and Ukraine, warned Friday that more EU sanctions could be leveled if the peace accords to stabilize Ukraine are not respected.

Hollande said at a joint press conference that "every country that doesn't keep its word" risks sanctions.

In Britain, a parliamentary report published Friday accused the British government and European diplomats of "sleepwalking" into the Ukraine crisis, saying there was a "catastrophic misreading" of the mood in Russia.

The House of Lords' EU Committee said foreign ministries in Britain and other European countries were poorly equipped to draw up an "authoritative response" to the crisis partly because they lack expertise on Russia.

The report said the 28-nation European Union had been too optimistic about Russia's democratic development, and as a result Europe failed to realize the depth of Russian hostility when the EU opened talks with Ukraine in 2013.

Elaine Ganley in Paris and Sylvia Hui in London contributed to this report.