A ceasefire agreement between the Ukrainian government and pro-Russian rebels has failed in the eastern town of Debaltseve, where Ukrainian forces were forced to flee following a massive assault by pro-Russian rebels on Wednesday.
"The actions by the Russia-backed separatists in Debaltseve are a clear violation of the ceasefire," said European Union foreign policy chief Federica Mogherini.
"The EU stands ready to take appropriate action in case the fighting and other negative developments in violation of the Minsk agreements continue."
Reuters reports that twenty-two Ukrainian soldiers had been killed in the key railroad hub in the past few days and over 150 wounded at the hands of the Russian separatists. According to the AP, over 2,000 of the remaining government troops left Debaltseve on Wednesday morning, looking defeated.
"Some were driving to the nearby town of Artemivsk in trucks while several others, unshaven and visibly upset, were on foot," reads the report. "One soldier spoke of heavy government losses, while another said they had not been able to get food for days because of the rebel shelling."
Meanwhile, the rebel group described the battle as a victory and said they permitted the Ukrainian troops to leave only after they were defeated.
"There were no attempts by Ukrainian forces to break through. The surrounded Ukrainian forces were completely demoralized. They lost their direction. They began shooting at residential areas of Debaltseve," a senior rebel commander, Eduard Basurin, boasted.
However, Ukrainian President Petro Poroshenko has called the withdrawal a tactical decision that "laid shame on Russia." He denied reports of large Ukrainian casualties and rebel claims of many soldiers captured, saying troops were leaving the town with their weapons and ammunition.
"Debaltseve was under our control, it was never encircled. Our troops and formations have left in an organized and planned manner," he said in televised comments.
Last week, the ceasefire was agree upon by Ukraine, Russia, Germany and France after over sixteen hours of peace talks in Minsk, Belarus.
"The main thing which has been achieved is that from Saturday into Sunday there should be declared without any conditions at all, a general ceasefire," Poroshenko told journalists at the time.
The leaders also agreed to honor and respect the "sovereignty and territorial integrity of Ukraine," recognizing that there is no alternative to an exclusively peaceful settlement. Rebel forces have since argued that the ceasefire did not apply to Debaltseve.
On Wednesday, Nato chief Jens Stoltenberg said the rebels' offensive had put the larger peace agreement at risk and urged Russia to "use all its influence on the separatists to make them respect the ceasefire".
However, Russian President Vladimir Putin, who helped broker the agreement last week, mocked the Ukrainian forces and suggested they should lay down their arms.
"Of course, it's always bad to lose," Putin told reporters, according to Fox News. "Of course it's always a hardship when you lose to yesterday's miners or yesterday's tractor drivers. But life is life. It'll surely go on."
Poroshenko and Western leaders have accused Russia of supporting the rebel group, arguing that the assault was reinforced by Russian tanks, artillery and soldiers-claims Russia has denied.
The U.S. has insisted that it has no interest of getting into a "proxy war" with Russia, but has not yet announced whether it will send lethal aid to the Ukrainian government in light of the recent attacks.
"Our belief here in the administration, and I would be surprised if others disagree, is that getting into a proxy war with Russia is not anything that's in the interest of Ukraine or in the interest of the international community," White House spokeswoman Jen Psaki told reporters. "And certainly, as we weigh options, we weigh that as one of the factors."