A top UN aid official meanwhile questioned "what has become of our basic humanity", as the war raged on in Gaza and humanitarian operations struggled to respond.

The United Nations has warned that the military operation which Israel launched in the West Bank early on Wednesday is "fuelling an already explosive situation" in the territory and has pressed Israel to end it.

In the United States, Vice President Kamala Harris pledged she would not change Washington's policy of supplying weapons to Israel if elected to the top job in November. But she stressed it was time to "end this war".

Israeli forces have killed at least 16 Palestinians in the raids since Wednesday, a toll confirmed by the Palestinian health ministry.

An AFP journalist reported loud explosions from the city's refugee camp and thick plumes of smoke rising from the area.

Israeli troops pulled back from other West Bank towns late Thursday but fighting raged on around Jenin, long a hub of militant activity.

Vaccination 'pauses'
 

In Gaza, Israeli artillery pounded western areas of Gaza City early Friday, an AFP journalist said. In contrast, a medical source at the southern Nasser Hospital said an Israeli strike killed three people near the southern city of Khan Yunis.

The World Health Organization said Israel had agreed to at least three days of "humanitarian pauses" in parts of Gaza, starting Sunday, to facilitate a vaccination drive after the first case of polio in a quarter of a century was recorded in the territory.

Israeli Prime Minister Benjamin Netanyahu said the measures were "not a ceasefire" in the nearly 11-month-old of the Israeli war on Gaza.

In the West Bank, the army said it killed seven Palestinians on Thursday, including five Palestinians in Tulkarem refugee camp.

A military statement said one of the five was Muhammad Jaber, also known as Abu Shujaa, who Palestinian militant group Islamic Jihad said was its commander in the nearby Nur Shams refugee camp.

Two other Palestinians were killed in Jenin on Thursday, the military said.

The Israeli assault has caused significant destruction, especially in Tulkarem, whose governor Mustafa Taqatqa described the raids as "unprecedented" and a "dangerous signal".

The Palestinian Prisoners' Club advocacy group said at least 45 people had been detained in the West Bank since Wednesday. An Israeli military spokesman said, "10 wanted individuals were arrested".

Violence has surged in the West Bank since October 7.

The United Nations said on Wednesday that at least 637 Palestinians had been killed in the territory by Israeli troops or settlers since the Gaza war began.

Nineteen Israelis, including soldiers, have been killed in Palestinian attacks or during army operations over the same period, according to Israeli official figures.

'Basic sense of humanity'
 

In Gaza, the Israeli military said Thursday it had "eliminated dozens" of Palestinians in a day of combat and strikes.

Israeli shelling in the Jabalia refugee camp killed two people on Friday, the civil defence agency in the Hamas-ruled territory said.

The UN had to halt the movement of aid and aid workers within Gaza on Monday due to a new Israeli evacuation order for the Deir el-Balah area, which had become a hub for its workers.

"More than 88 per cent of Gaza's territory has come under an (Israeli) order to evacuate at some point," the acting head of the UN humanitarian office, Joyce Msuya.

She said civilians were being forced into just 11 per cent of the Gaza Strip, already one of the most densely populated territories in the world before the war.

"What we have witnessed over the past 11 months... calls into question the world's commitment to the international legal order designed to prevent these tragedies," Msuya said.

"It forces us to ask: what has become of our basic sense of humanity?"

Israel's military campaign has killed at least 40,602 people in Gaza, mostly women and children, according to the territory's health ministry. The UN rights office says most of the dead are women and children.

The war has devastated Gaza, repeatedly displaced most of its 2.4 million people and triggered a humanitarian crisis.

In central Gaza, some Palestinians returned to parts of Deir el-Balah after the military had amended a previous evacuation order.

Mohamed Abu Thuria told AFP he had "found massive destruction everywhere".

Another displaced Gazans back in Deir el-Balah, Ibrahim al-Tabaan, said: "We lost everything."