DONETSK, Ukraine (AP) — Fighting raged in the city of Donetsk on Sunday, as government forces continued to close in on the rebel stronghold and pro-Russian insurgents backed away from an unconditional cease-fire offer that they announced just the day before.

With a string of military successes and broad support for its campaign from the West and most of its domestic base, Kiev has taken a hard line against the rebel forces and promised it will only relent when the separatists surrender. Donetsk remained a ghost town on Sunday, with few civilians daring to venture outside as explosions rang out every few minutes and burnt-out buses and buildings smoldered from the night before.