The military said it was entering “a new stage” of fighting against the Hamas terror group in the Gaza Strip on Thursday, as troops prepared to cut off the southern city of Rafah and warplanes carried out extensive strikes across the enclave, amid warnings of further attacks.

Hamas-controlled health authorities in the Strip reported dozens killed in Israeli strikes over the previous 24 hours, including 27 people who died when three missiles hit a former school building in the al-Tuffah neighborhood of Gaza City, though the tolls could not be confirmed.

Israeli authorities said warplanes had targeted “key Hamas terrorists” inside a command center used to plan and execute attacks against Israelis and that it had taken steps to mitigate harm to civilians.

The intensification in fighting came a day after Prime Minister Benjamin Netanyahu announced that troops would carve out a new security corridor that will seemingly cut off Rafah as it seeks to pile pressure on Hamas, which continues to hold 59 Israeli hostages kidnapped on October 7, 2023.

“In recent days, we have advanced to a new stage in the operation,” Israel Defense Forces spokesman Brig. Gen. Effie Defrin told reporters Thursday in his first briefing since assuming the post earlier this week. “The plan serves the goals of the war: returning the hostages and destroying Hamas’s military and governing capabilities.”

He spoke a day after the IDF deployed a new division into southern Gaza, bringing the number of divisions operating in the Strip to three.

Defrin said the newly expanded campaign had involved more than 60 airstrikes aimed at degrading Hamas’s capabilities and paving the way for ground troops to move into areas in the north and south of the Strip.

“We have broadened our activities in southern Gaza to surround and cut off the Rafah area,” he added. “Beyond that, we’re maintaining operational ambiguity so we can surprise the enemy and bring about significant achievements.”

Thursday also saw a rocket fired at Israel from central Gaza, setting off sirens in the border community of Nahal Oz. The projectile was intercepted by air defenses, the army said.

There have been a number of sporadic rocket attacks from Gaza since the IDF resumed its offensive last month, after a ceasefire and hostage release deal in place since January fell apart, with Israel vowing to ratchet up military pressure on Hamas to free the remaining hostages. The war, which has devastated the Strip, was sparked when thousands of Hamas terrorists invaded southern Israel on October 7, killing some 1,200 people and kidnapping 251. Most victims were civilians.

The army also said Thursday that a strike a day earlier against a Hamas command center in northern Gaza’s Jabalia had killed at least four operatives, including a terrorist who participated in the October 7 onslaught and another Palestinian who was involved in the release ceremony of hostage soldier Agam Berger. Two Hamas members involved in launching rockets were also killed, the army said.

Palestinians had reported that 19 people were killed and claimed the site was a clinic run by the UN agency for Palestinian refugees.

According to Defrin, since the resumption of fighting in Gaza on March 18, Israel has struck more than 600 targets in the Strip and killed over 250 terror operatives, including 12 senior officials in Hamas’s military wing and politburo.

“They are all terrorists and participated in the October 7 massacre,” he said of the senior officials.

Following the rocket fire Thursday, which was claimed by the Islamic Jihad terror group, the IDF warned residents of several Gaza City neighborhoods to flee, saying it was issuing a “final warning” before strikes there.

Earlier in the day, hundreds of residents streamed out of the Gaza City suburb of Shejaiya after Israel warned civilians to evacuate ahead of strikes. Some were seen carrying their belongings as they walked, while others were on donkey carts and bikes or in vans.

Throughout the war, the IDF has issued evacuation orders for various areas, advising residents to head for safe zones to avoid being caught up in the fighting. Israel accuses Hamas of using civilians as human shields by embedding its fighters among the population.

Palestinians said people in Rafah who tried to leave the city Thursday were hampered by Israeli strikes along the western coastal road linking Rafah to Khan Younis, where many displaced Gazans have already moved to. Most Gazans had already fled the city when Israel resumed its campaign last month.

Rafah “is gone, it is being wiped out,” a father of seven who fled from Rafah to Khan Younis told Reuters via a chat app.

“They are knocking down what is left standing of houses and property,” said the man, who declined to be identified for fear of repercussions.

On Wednesday, Netanyahu said Israel was “shifting gears” in Gaza and seizing a belt of land known as the “Morag Corridor,” cutting off access between Rafah and the city of Khan Younis to the north. The move will essentially isolate Rafah, which is bounded on the south by the Israel-controlled Philadelphi Route along the Gaza-Egypt border.

Israel has also reasserted control over the Netzarim Corridor, which separates the northern third of Gaza from the rest of the narrow strip.

“We are now cutting off the Strip and we are increasing the pressure step by step… so they will give us our hostages. The longer they refuse to give them up, the more the pressure will increase until they do,” Netanyahu said.

Hamas has said it will only release the remaining 59 hostages — 24 of whom are believed to be alive — in exchange for the release of more Palestinian prisoners, a permanent ceasefire and an Israeli pullout. The group has rejected demands that it lay down its arms or leave the territory.

Hamas-controlled health officials said on Thursday that 1,163 people have been killed in the Palestinian territory since Israel resumed large-scale strikes, bringing the overall death toll since the war began to 50,523. The toll does not differentiate between fighters and civilians. Israel says it killed at least 20,000 combatants and another 1,600 terrorists inside Israel on October 7.