The Israeli military on Friday mistakenly killed three Israeli hostages during its ground operation in the Gaza Strip, military officials said.

The army’s chief spokesman, Rear Adm. Daniel Hagari, said Israeli troops found the hostages and erroneously identified them as a threat.

He said it was not clear if they had escaped their captors or been abandoned.

The deaths occurred in the Gaza City area of Shijaiyah, where troops have engaged in fierce battles against Hamas militants in recent days.

He said the army expressed “deep sorrow” and was investigating.