Pro-Russian rebels in Donetsk and Luhansk have theoretically been under a cease-fire with Ukrainian forces since September. But the agreement was always tenuous, and recent clashes had pushed it to the brink of collapse. Zakharchenko's deputy, Eduard Basurin, was quoted by the separatist-run Donetsk News Agency on Friday as saying that separatists no longer recognized the agreement signed in Minsk, Belarus - although, he added, the rebels were open to negotiations.