Fierce fighting has killed nearly 300 Palestinians in the past 24 hours in Gaza as the Palestinian armed group Hamas and Israeli Prime Minister Benjamin Netanyahu exchanged threats.

Israeli raids continued across the besieged territory on Sunday, including in northern Gaza where entire neighbourhoods have been flattened by air strikes and where ground troops that have been operating for more than six weeks continue to face heavy resistance from Hamas fighters.

Gaza’s health ministry spokesman Ashraf al-Qudra told Al Jazeera in a telephone interview that 297 people were killed and more than 550 wounded in the past 24 hours in Gaza, bringing the death toll since the start of the war on October 7 to more than 18,000 – the majority of them women and children.

Hamas, Netanyahu exchange threats

Israeli attacks on Gaza continued for the 65th day on Sunday, with Hamas warning that no captives it took on October 7 would leave Gaza alive unless its demands were met.

“Neither the fascist enemy and its arrogant leadership… nor its supporters… can take their prisoners alive without an exchange and negotiation and meeting the demands of the resistance,” Hamas spokesman Abu Obeida said in a televised broadcast.

Israeli Prime Minister Benjamin Netanyahu, on his part, called on Hamas to surrender.

“It is the beginning of the end of Hamas. I say to the Hamas terrorists: It’s over. Don’t die for [Yahya] Sinwar. Surrender now,” he said, referring to the Hamas chief in Gaza.

Hamas earlier said Israel launched a series of “very violent raids” targeting the southern city of Khan Younis and the road linking it to Rafah near the border with Egypt.

Gaza residents also reported fierce fighting in Gaza City’s neighbourhood of Shujayea and in the Jabalia refugee camp, a dense urban area.

The Palestinian Red Crescent Society (PRCS) said Israeli forces raided an area near the UNRWA clinic in the heart of the Jabalia camp where its emergency teams and medics are operating a medical post.

“The team consists of nine doctors, nurses, and volunteers. The surrounding area is currently under bombardment, posing a constant threat to the lives of medical teams and the wounded,” the Red Crescent said in a post on X on Sunday evening.

🚨IOF has invaded the area near the UNRWA clinic in the midest of the Jabalia camp, where the PRCS EMS teams 🚑operate an advanced medical post. The team consists of 9 doctors, nurses, and volunteers. The surrounding area is currently under bombardment, posing a constant threat… pic.twitter.com/JcFpL1IRRS

— PRCS (@PalestineRCS) December 10, 2023

In Shujayea – where Israeli snipers and tanks positioned themselves among the abandoned buildings – residents said the dead and wounded were left in the streets as ambulances could no longer reach the area.

“They are attacking anything that moves,” Hamza Abu Fatouh told the Associated Press.

‘Journey of death’

Israel had ordered the evacuation of northern Gaza early in the war but tens of thousands of people have remained, fearing that the south would be no safer or that they would never be allowed to return home.

Heavy fighting was also under way in and around the southern city of Khan Younis on Sunday.

“The mass exodus continues. Those fleeing northern Gaza in order to survive are describing it as the ‘journey of death’,” said Al Jazeera’s Tareq Abu Azzoum, reporting from Rafah in southern Gaza.

“Those in Khan Younis have been ordered to flee to al-Mawasi on the coastline – an area considered to be very dangerous,” he added.

“It’s also a region without any infrastructure – including access to water, food and electricity. There’s also no access to toilets. The situation is deteriorating extremely fast now.”

Gaza’s health situation ‘catastrophic’: WHO

The World Health Organization’s 34-member executive board on Sunday adopted a resolution calling for immediate, unimpeded aid deliveries to Gaza.

“Gaza’s health system is on its knees and collapsing,” said WHO chief Tedros Adhanom Ghebreyesus, with only 14 of 36 hospitals functioning at any capacity.

The emergency action, proposed by Afghanistan, Qatar, Yemen and Morocco, seeks passage into Gaza for medical personnel and supplies, requires the WHO to document violence against healthcare workers and patients, and to secure funding to rebuild hospitals.

“I must be frank with you: these tasks are almost impossible in the current circumstances,” Tedors said, commending the countries for finding common ground and saying it was the first time any United Nations motion had been agreed to by consensus since the conflict began.

About 90 percent of Gaza’s 2.3 million residents have been displaced within the territory. With very little aid allowed in, Palestinians are facing severe shortages of food, water and other basic goods.

Mustafa Barghouti, a Palestinian politician who heads the Union of Palestinian Medical Relief Committees with 25 teams working in Gaza, said: “Half of Gaza is now starving.”

Barghouti said 350,000 people had infections including 115,000 with severe respiratory infections and lacking warm clothes, blankets and protection from the rain.

He said many were suffering from stomach complaints because there was little clean water and not enough fuel to use to boil it, risking outbreaks of dysentery, typhoid and cholera.

“To add insult to injury, we have 46,000 injured people who cannot be treated properly because most of the hospitals are not functioning,” he said.

Renewed US support to Israeli attacks

Israel intensified its bombardment on Gaza after the latest United States veto on a UN Security Council resolution calling for a ceasefire. The vote was triggered by UN Secretary-General Antonio Guterres who invoked Article 99 of the UN Charter – a measure unused in decades.

The article allows the Secretary-General to “bring to the attention of the Security Council any matter which in his opinion may threaten the maintenance of international peace and security”.

The US also pushed through an emergency sale of about 14,000 tank shells worth more than $100m to Israel without congressional review, the Pentagon said on Saturday.

Fending off criticism over the sale from Palestinians and rights groups who say it does not align with Washington’s stated effort to press Israel to minimise civilian casualties, US Secretary of State Antony Blinken told ABC on Sunday that Washington is in almost constant contact with the Israelis “to ensure they understand what their obligations are”.

In an address to the two-day Doha Forum event that started in the Qatari capital on Sunday, Antonio Guterres said he expected the “public order to completely break down soon” in Gaza.

“And an even worse situation could unfold, including epidemic diseases and increased pressure for mass displacement into Egypt,” he added.

Qatar, a key mediator of last month’s seven-day truce, which saw 80 Israeli captives exchanged for 240 Palestinian prisoners and a flow of humanitarian aid, on Sunday said it was still working on a new truce deal.

Qatar’s Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani told the Doha Forum that mediation efforts will continue to stop the war and have all captives released, but “unfortunately, we are not seeing the same willingness that we had seen in the weeks before”.

“Our efforts as the state of Qatar along with our partners are continuing,” he said, adding that Israel’s relentless bombardment was “narrowing the window” for success.