Hamas must disarm and recognise Israel under a Palestinian unity deal announced on Thursday with its rival Fatah aimed at ending their decade-long split, an Israeli government official said.
"Any reconciliation between the (Fatah-dominated Palestinian Authority) and Hamas must include a commitment to international agreements and to the conditions of the Quartet, first of which is recognising Israel and demilitarising Hamas," the official said in the Israeli government's first reaction to the deal signed in Cairo.
The official was referring to the diplomatic Quartet on Middle East peace, which includes the United Nations, the United States, the European Union and Russia.
The reaction was Israel's first after the two major Palestinian factions agreed a unity deal in the Egyptian capital on Thursday afternoon, which is supposed to see the internationally recognised Palestinian Authority retake control of Gaza from Islamists Hamas by December 1.
The publicly-released parts of the agreement did not specify what would happen to Hamas' armed wing.
Hamas does not recognise Israel and has fought three wars with the Jewish state since 2008.
"As long as Hamas remains armed and as long as it calls for the destruction of Israel, Israel will consider Hamas responsible for any terror attack originating from Gaza," the official said.
He also demanded an immediate return of the bodies of two Israeli soldiers killed by Hamas in 2014, as well as the release of two citizens believed imprisoned by the Islamists.