Heavy fighting raged overnight and into Sunday in the southern Gaza town of Khan Younis, as Israel pressed ahead with its offensive after the US blocked the latest international efforts to halt the fighting and rushed more munitions to its close ally.

Israel has faced rising international outrage and calls for a cease-fire after the killing of thousands of Palestinian civilians and the displacement of nearly 85 per cent of Gaza's 2.3 million people within the besieged territory, where UN agencies say there is no safe place to flee.

But the United States has lent vital support to the offensive once again in recent days, by vetoing United Nations Security Council efforts to end the fighting that enjoyed wide international support, and by pushing through an emergency sale of over USD 100 million worth of tank ammunition to Israel.

The US has pledged unwavering support for Israel's goal of crushing Hamas' military and governing abilities in order to prevent any repeat of the October 7 attack that triggered the war.

Hamas and other Palestinian militants stormed into southern Israel that day, killing some 1,200 people and capturing some 240, over 100 of whom were released during a weeklong cease-fire late last month.

In response to the attack, Israel launched a devastating air and ground war that has killed thousands of Palestinians, mostly civilians, and forced some 1.9 million people to flee their homes, according to UN agencies.

With only a trickle of aid allowed in, and delivery rendered impossible in much of the territory, Palestinians face severe shortages of food, water and other basic goods.

Israeli forces continue to face heavy resistance, even in northern Gaza, where entire neighbourhoods have been flattened by air strikes and where troops have been operating for over six weeks.

In Khan Younis, where ground forces moved in earlier this month, residents said they heard constant gunfire and explosions through the night as warplanes bombarded areas in and around the southern city, Gaza's second largest.

“It doesn't stop,” said Radwa Abu Frayeh, who lives close to the European Hospital in Khan Younis. "There's bombing, and then the ambulances head out to bring back victims."

DETENTIONS IN THE NORTH

Israel ordered the evacuation of the northern third of the territory, including Gaza City, early in the war, but tens of thousands of people are believed to have remained there, fearing that the south would be no safer or that they would never be allowed to return to their homes.

In recent days, videos and photos have emerged showing the detention of dozens of men who were stripped to their underwear, bound and blindfolded.

The Israeli military says it is detaining people as it searches for remaining pockets of Hamas fighters.

Israel's Channel 13 TV broadcast footage showing dozens of detainees stripped to their underwear with their hands in the air. Several held assault rifles above their heads, and one man could be seen slowly walking forward and placing a gun on the ground before returning to the group. Israeli media pointed to such scenes as evidence that Hamas was collapsing in the north.

Men from a separate group of detainees who were released on Saturday told The Associated Press they had been beaten and denied food and water.

Osama Oula said Israeli troops had ordered him and others out of a building in Gaza City before bounding their hands with zip ties, beating them for several days and giving them little water to drink. Ahmad Nimr Salman showed his hands, marked and swollen from the zip ties.

He said the troops asked if they were with Hamas. "We say no,' then they would slap us or kick us." He said his 17-year-old son Amjad is still held by the troops.

The group was released after five days and told to walk south. Ten freed detainees arrived at a hospital in Deir al-Balah on Saturday after flagging down an ambulance. The Israeli military had no comment when asked about the alleged abuse.

NO SAFE PLACES

With the war in its third month, the Palestinian death toll in Gaza has surpassed 17,700, the majority women and children, according to the Health Ministry in the Hamas-controlled territory. The ministry does not differentiate between civilian and combatant deaths.

Israel holds Hamas responsible for civilian casualties, saying it uses civilians as human shields in dense residential areas. The military says 97 Israeli soldiers have died in the ground offensive. Palestinians militants have also continued firing rockets into Israel.

Israel says it has provided detailed instructions for civilians to evacuate to safer areas, even as it continues to strike what it says are militant targets in all parts of the territory. Thousands have fled to the southern town of Rafah and other areas along the border with Egypt in recent days — one of the last areas where aid agencies are able to deliver food and water.

Israel has designated a narrow patch of barren southern coastline, Muwasi, as a safe zone. But Palestinians described desperately overcrowded conditions with scant shelter and no toilets. They faced an overnight temperature of around 11 degrees Celsius (52 degrees Fahrenheit).

“I am sleeping on the sand. It's freezing,” said Soad Qarmoot, who described herself as a cancer patient forced to leave her home in the northern town of Beit Lahiya.

As she spoke, her children huddled around a fire.