In an apparent turn-around of decision, Israel mounted its military operation in northern Gaza as it saw some of the heaviest clashes since New Year on Tuesday.

Israeli tanks stormed back into parts of the northern Gaza Strip they had left last week when Israel announced it was scaling back its operations there, residents said Tuesday.

Massive explosions could be seen over northern areas of Gaza from across the border with Israel – a rarity over the past two weeks after Israel announced a draw-down of forces in the north as part of a transition to smaller, targeted operations.

The rattle of intense gunfire carried across the border through the night. In the morning, contrails snaked through the sky as Israel's Iron Dome defenses shot down rockets fired by Palestinian resistance groups across the fence.

Israel claimed its forces had killed dozens of resistance members overnight in clashes in Beit Lahiya on the northern edge of the Gaza Strip.

Gaza health authorities said the last 24 hours of Israeli bombing had killed 158 people in the enclave, raising their toll for the war, now in its fourth month, to 24,285, with thousands more bodies feared lost in the rubble.

Israel launched the war following the Oct. 7 Hamas incursion killed 1,140 people and captured 240 hostages.

The war has driven nearly all Gazans from their homes, some several times, and caused a humanitarian crisis, with food, fuel and medical supplies running low.

Under pressure from Washington to reduce civilian casualties, Israel had said it was shifting tactics, transitioning from a full-scale ground assault to targeted operations against Hamas.

It began that shift with a pullback in the north, where its forces had begun their ground offensive in October. On Monday evening, Defence Minister Yoav Gallant also said the more recent ground assault in the south was drawing to a close.

But any path toward de-escalating the war still seems remote, with Israel saying it will not halt until Hamas is destroyed. Israeli officials said Hamas rockets hit an electronics shop in southern Israel on Tuesday morning. There were no immediate reports of casualties.

Some of the hundreds of thousands of residents who fled the north earlier in the war had begun returning last week to bombed-out areas where the Israelis had withdrawn. But residents who spoke to Reuters on Tuesday said the abrupt resurgence of fighting in the north would now halt plans to try to go home.

"We almost planned to return to our house in Nazla, east of Jabalia, but thank God we didn't. This morning people living nearby arrived here and told us the tanks pushed back there," said Abu Khaled, 43, a father of three now living with relatives in severely damaged Gaza City.

"The sounds of bombing from the tanks, from the planes didn't stop all night. It reminded us of the first day of the ground incursion," he said. "I will only believe tanks are out when a ceasefire agreement is announced."

'Forgive me, my son"

In the south of the enclave, Israeli forces have fought their way to the center of the main southern city Khan Younis, and into towns north and east of the central city of Deir al-Balah.

Defense Minister Gallant's announcement Monday that the major ground offensive in the south was soon coming to an end raises the question of whether the Israelis will still try to advance into the remaining southern areas.

Most of Gaza's 2.3 million people are now crowded into the few southern areas that Israeli troops have yet to enter, including Deir al-Balah and Rafah, which is located on the southern edge of the strip.

In Khan Younis, Zaher Abu Zarifa wept and cradled a black plastic body bag holding his 7-year-old son Saif, one of at least 11 bodies brought out at a hospital morgue.

The boy was killed, his father said, by a missile while playing on a bicycle by a school gate. Later, by a small freshly dug grave, a gravedigger unzipped the bag so the father could kiss the boy's face, then zipped it back up, took the boy and gently laid him in the ground.

"Forgive me, my son. I could not protect you," the father repeated. "Forgive me, my son. I could not protect you."

In Rafah, residents were combing the rubble of the house of the Ibn Germy family, which had been bombed overnight.

"What is their fault? They were having dinner, we want peace not war," said neighbor Salem al-Loulahy.