Israeli Defence Minister Israel Katz threatened to annex parts of the Gaza Strip unless Hamas militants release the remaining Israeli hostages held in the war-battered Palestinian territory. Israel stepped up its assault on Gaza, shattering the relative calm that had reigned since a January ceasefire. Katz also threatened to expand buffer zones around Gaza to protect Israeli civilians and soldiers. Thousands of protesters have rallied in Jerusalem, accusing Prime Minister Benjamin Netanyahu of resuming military operations without regard for the safety of the hostages.