Similar leaflets had already been dropped about two weeks earlier but this time they were followed by heavy Israeli tank shelling on eastern neighbourhoods.

Khan Younis is located in the southern half of the Gaza Strip. Tens of thousands of people displaced from the north have already sought refuge there in schools and tents, causing severe overcrowding amid shortages of food and water.

"For your safety, you need to evacuate your places of residence immediately and head to known shelters," the leaflets said, naming the neighbourhoods of Khuzaa, Abassan, Bani Suhaila and Al Qarara.

"Anyone near terrorists or their facilities puts their life at risk, and every house used by terrorists will be targeted," the leaflets said.

Two thirds of the Gaza Strip's population of 2.3 million have been made homeless by the war and every available space in Khan Younis and other southern towns is already crammed.

The U.N. human rights chief said on Thursday that outbreaks of infectious diseases and hunger seemed inevitable given the dire living conditions and intensity of crowding.

Israel has also used leaflet drops in northern Gaza to put pressure on civilians to move, and hundreds of thousands have done so, a mass displacement that many Palestinians fear could become permanent.

The war was triggered by Hamas militants who rampaged through southern Israel on Oct. 7, killing some 1,200 people, including babies and children, and taking more than 200 back to Gaza as hostages, according to Israel.

Israel vowed to destroy Hamas and launched an air, sea and ground assault on densely populated Gaza that has killed more than 11,000 people, most of them women and children, according to Gazan health officials.

Israel has come under increasing international pressure to change course in Gaza as the humanitarian crisis in the enclave has escalated.