Russia said Wednesday that nearly 1,000 Ukrainian troops making their last stand in Mariupol have surrendered, edging ever closer to the end of the battle that turned the city into a symbol of resistance and suffering.

The fighters trooping out of the ruins of the sprawling Azovstal steel mill, carrying their wounded with them and leaving a dwindling number still inside the plant, face an uncertain fate. Ukraine says it hopes for a prisoner swap but Russia has said at least some could be investigated for war crimes.

Russia called the slow but steady abandonment of the last redoubt of resistance a surrender, but Ukraine avoided that word. It’s unclear how many fighters remain inside plant’s warren of tunnels and bunkers, where 2,000 were believed to be holed up at one point. Also unclear is the status of the garrison’s commanding officers.