Israel's new offensive in Gaza City could take weeks to start, leaving the door open for a ceasefire, officials say, even as Prime Minister Benjamin Netanyahu said it would get underway "fairly quickly" and end the war with Hamas' defeat.

Israel's security cabinet has approved plans by Prime Minister Benjamin Netanyahu for the Israeli military to occupy Gaza City, in an expansion of military operations that comes amid international condemnation of the deteriorating humanitarian situation in the Gaza Strip.

Defending his plan in a press conference in Jerusalem, Benjamin Netanyahu said the new operation would be implemented on "a fairly short timetable