ENLARGE Ukrainian soldiers who left Debaltseve on Wednesday prepare to return to support the further withdrawal of troops on Thursday in Artemivsk. Photo: Getty Images European leaders on Thursday stood by the cease-fire they brokered a week ago for Ukraine, even as the U.S. said Russian equipment and troops continued to flow into the country and the Ukrainian military significantly raised its latest casualty toll. Kiev and its Western backers had denounced a dayslong offensive by Russia-backed separatists to seize the strategic rail hub of Debaltseve as a violation of the cease-fire. But as fighting subsided generally after the hasty retreat on Wednesday by Ukrainian forces, none of the parties appeared willing to declare the latest deal dead. “The four leaders agreed to rigorously implement the entirety of the package of measures” agreed to on Feb. 12, the office of French President François Hollande said after the conference call […]