JERUSALEM — Israel announced a major expansion of military operations in Gaza on Wednesday, saying large areas of the Palestinian territory would be seized and added to its security zones, accompanied by large-scale evacuations of the population.

In a statement, Defense Minister Israel Katz said evacuations would take place from areas where there was fighting, while urging Gazans that only eliminating Hamas and returning Israeli hostages can end the conflict.

The operation would clear out militants and infrastructure "and seize large areas that will be added to the security zones of the State of Israel", he said.

A group representing families of hostages held in Gaza said they were "horrified" by Katz's announcement, fearing the goal of freeing the captives had been "pushed to the bottom of the priority list".

"Has it been decided to sacrifice the hostages for the sake of 'territorial gains'?" the Hostages and Missing Families Forum asked.

"Instead of freeing the hostages through a deal and putting an end to the war, the Israeli government is sending more soldiers to Gaza, to fight in the same areas where they have fought again and again."

Basem Naim, a senior Hamas official, told Reuters that Israeli hostages would only be released through negotiations, not via military pressure.

The Israeli military had already issued evacuation warnings to Gazans living around the southern city of Rafah and toward the city of Khan Younis, telling them to move to the Al-Mawasi area on the shore, previously designated a humanitarian zone.

Gaza's Health Ministry said 41 people were killed in Israeli strikes on Wednesday, with 19 killed in a strike at a United Nations clinic being used to house displaced people.

The Israeli army said it struck the militants "inside a command and control center that was being used for coordinating terrorist activity", and separately confirmed to Agence France-Presse that the building housed a UN clinic.

Gaza's civil defense agency said nine children were among the 19 dead.

Israel's renewed offensive in Gaza has reportedly left at least 322 children dead and 609 wounded in the past 10 days, the United Nations agency for children said on Monday.

Palestinian radio reported that the area around Rafah was almost completely empty following the evacuation orders.

At the site of a strike in Khan Younis, Rida al-Jabbour held up a tiny shoe and pointed at a blood-spattered wall as she related how a neighbor had been killed along with her 3-month-old baby.

"From the moment the strike occurred, we have not been able to sit or sleep or anything," she said, describing how rescue workers were unable to separate the remains of those killed.

In Gaza City, hunger loomed as bakeries were shut because of severe shortages of flour and sugar.

"I've been going from bakery to bakery all morning, but none of them are operating, they're all closed," Amina al-Sayed told Agence France-Presse.

Further pressure

Katz's statement did not make clear how much land Israel intended to seize or whether the move represented a permanent annexation of territory — which would add further pressure on a population already living in one of the most crowded areas in the world.

According to the Israeli rights group Gisha, Israel has taken control of some 62 square kilometers or about 17 percent of the total area of the Gaza Strip, as part of a buffer zone around the edges of the enclave.

Seizing the buffer zone, which contains infrastructure, including wells, sewage pumping stations and wastewater treatment facilities, as well as a significant part of Gaza's agricultural land, would also increase pressure on the enclave's ability to sustain itself.

Agencies - Xinhua