Israeli Defence Minister Israel Katz says the military will expand its operation in Gaza and seize "large areas" of the territory - incorporating them into what he described as "security zones."

In a statement on Wednesday, Katz said the expanded operation aimed to "destroy and clear the area of terrorists and terrorist infrastructure", and would require a large-scale evacuation of Palestinians.

It comes as local hospitals said at least 15 Palestinians were killed in the territory overnight.

The Hamas-run civil defence agency said first responders had recovered the bodies of 12 people, including children, from a home in the Khan Younis area.

There have been reports of extensive Israeli air strikes and shelling along the Egypt border and there is a growing sense that a new major Israeli ground offensive is looming in Gaza.

This week, Israel's military ordered an estimated 140,000 people in Rafah to leave their homes and issued new evacuation orders for parts of northern Gaza.

Israel has already significantly expanded a buffer zone around the edge of Gaza over the course of the war, and seized control of a corridor of land cutting through its centre.

Israel launched its renewed Gaza offensive on 18 March, blaming Hamas for rejecting a new US proposal to extend the ceasefire and free the 59 hostages still held captive in Gaza.

Hamas, in turn, accused Israel of violating the original deal they had agreed to in January.

The Hostages and Missing Families Forum in Israel said they were "horrified to wake up" to the news of the expanded military operation. In a statement, the group urged the Israeli government to prioritise securing the release of all hostages still held in Gaza.

In his statement announcing plans to seize more territory, Katz also urged Gazans to act to remove Hamas and free remaining Israeli hostages, without suggesting how they should do so.

The humanitarian situation across Gaza has dramatically worsened in recent weeks, with Israel refusing to allow aid into the Gaza Strip since 2 March - the longest aid blockage since the war began.

Last month the UN announced it was reducing its operations in Gaza, one day after eight Palestinian medics, six Civil Defence first responders and a UN staff member were killed by Israeli forces in southern Gaza.

The Israeli military launched a campaign to destroy Hamas in response to an unprecedented cross-border attack on 7 October 2023, in which about 1,200 people were killed and 251 were taken hostage.

More than 50,399 people have been killed in Gaza during the ensuing war, according to the Hamas-run health ministry.