Displaced Palestinians leave an area in east Khan Yunis after the Israeli army issued a new evacuation order. AFP

More than 180,000 Palestinians have fled fierce fighting around the southern Gaza city of Khan Yunis in four days, the United Nations said Friday, after an Israeli operation to extract captives' bodies from the area.

Recent "intensified hostilities" in the Khan Yunis area, more than nine months into the Israel-Hamas war, have fuelled "new waves of internal displacement across Gaza", said the UN humanitarian agency, OCHA.

It said that "about 182,000 people" have been displaced from central and eastern Khan Yunis between Monday and Thursday, while "hundreds of other people remain stranded in eastern Khan Yunis".

The Israeli military on Monday issued evacuation orders for parts of the southern city, announcing its forces would "forcefully operate" there, including in a area previously declared a safe humanitarian zone.

On Wednesday, Israel said five bodies of captives seized during Hamas's October 7 attack that triggered the war had been recovered from the area.

The Israeli military on Monday issued evacuation orders for parts of the southern city.

Since the latest fighting began in Khan Yunis this week, Israel's military said on Friday that its forces had "eliminated approximately 100 terrorists" in the city.

Israel's military Herzi Halevi said the captives' bodies were pulled from underground tunnels and walls in "a hidden place".

Troops "were near those fallen bodies in the past, we did not know how to reach them" until this week, Halevi said in a statement issued by the military.

Witnesses and rescuers said heavy battles continued on Friday around eastern Khan Yunis, where the civil defence agency said shelling killed at least two people in a house.

The October 7 attack on southern Israel resulted in the deaths of 1,197 people, most of them civilians, according to an AFP tally based on official Israeli figures.

Out of 251 people taken hostage that day, 111 are still held in the Gaza Strip, including 39 the military says are dead.

Israel's retaliatory offensive against Hamas has killed at least 39,175 Palestinians in Gaza, according to the Hamas-run territory's health ministry.

According to UN figures, the vast majority of Gaza's 2.4 million people have been displaced at least once by the fighting.

Agence France-Presse