The announcement came just days after the Israeli government revealed plans to seize large areas of the strip with an operation in the south.
Israel issued evacuation warnings in the area on April 3, which saw hundreds of residents leave, with some carrying their belongings as they walked and others transporting them on donkey carts, bikes, or vans.
The Hamas-run health authorities said Israeli forces killed at least 27 people, including women and children, in an airstrike on a school building in Gaza City where displaced families were sheltering.
The IDF stated that the Dar Al-Arqam school building in the Tuffah area of Gaza City had been used as a command and control center by Hamas and accused the terrorists of deliberately secreting their bases within civilian infrastructure.
Hamas denies that it operates among civilians.
Hundreds of thousands of Palestinians have left their homes in recent days in one of the biggest mass exoduses of the war, as Israeli forces have moved to expand the territory they control.
On the southern edge of the strip, Israeli troops have been massing around the already heavily bombed city of Rafah.
Israel has left some ambiguity as to its long-term aim for the areas now in the “security zone.”
Some Gazans say they believe that the aim is to permanently depopulate the area.
Israeli Prime Minister Benjamin Netanyahu said Israel was also establishing a new security corridor.
The Morag Corridor will run between the Israeli frontier and the sea between Rafah and Khan Yunis in southern Gaza. It bears the name of a Jewish settlement between the two cities that was evacuated in 2005.
During the war’s first 15 months of fighting, Israel also established the Netzarim Corridor, cutting off Gaza City and the northern strip from the rest of Gaza.
The IDF has reasserted control of it during the current round of fighting.
“We are now dividing the Strip and increasing the pressure step by step so that they will give us our hostages. And as long as they do not give them to us, the pressure will increase until they do,” Netanyahu said.

The IDF stated that numerous militants had been killed and that they had dismantled infrastructure, including a Hamas command and control center.
Palestinians say Israel’s ultimate aim is to displace Gaza’s population permanently, in line with a plan mooted by U.S. President Donald Trump to turn the enclave into a waterfront resort under U.S. control.
The Jewish state says it would encourage Palestinians who wish to leave voluntarily to do so.
IDF troops resumed their operation in Gaza on March 18, after a two-month truce, and ministers have said that the operation will continue until the 59 hostages still held in Gaza by Hamas are returned.
The terrorist group, which runs the enclave, says it will free the hostages only under a deal that brings a permanent end to the war.