Pope Francis gestures during an audience to Members of the committee and the foundation World Youth Day Lisbon 2023 on November 30, 2023 at Paul-VI hall in The Vatican. (AFP)

VATICAN CITY, Holy See -- Pope Francis said Sunday that he was saddened the truce in the Gaza Strip had been broken and urged those involved in the conflict to reach a new ceasefire deal as soon as possible.

"There is so much suffering in Gaza," the pontiff said in comments from his private residence, which were read by an aide and broadcast on giant screens in Saint Peter's Square.

The 86-year-old is suffering from a lung infection that has caused breathing difficulties, and forced him to cancel a trip to Dubai to attend the international COP28 climate summit.

"Still today, I cannot read this all. I'm doing better, but my voice...," Francis said, before the aide took over.

In the comments, Francis said the end of the ceasefire meant "death, destruction, misery", stressing that the besieged Palestinian territory lacked even essential supplies.

He said the situation in Israel and the occupied Palestinian territories was "serious". "Many hostages have been freed but so many others are still in Gaza," he said.

Fighting between Israel and Hamas raged on Sunday for a third day since a week-long truce expired.

Hamas militants from Gaza launched an unprecedented attack on southern Israel on October 7, killing about 1,200 people, mostly civilians, and taking around 240 hostages, according to Israeli officials.

In response, Israel vowed to destroy Hamas and began an air, sea and ground offensive that has killed more than 15,500 people, mostly women and children, according to the health ministry in Hamas-run Gaza.

During the week-long pause in fighting, Hamas released 80 Israeli hostages in exchange for 240 Palestinian prisoners.

Twenty-five other captives, mostly Thais, were also freed under separate arrangements.

The Israeli army said 137 hostages were still being held in Gaza.

On day 58 of the war, here are five key developments from the past 24 hours:

At least 160 killed in two strikes 

The United Nations humanitarian agency (OCHA) said at least 160 Palestinian fatalities were reported in two incidents in northern Gaza Saturday: the bombing of a six-storey building in Jabalia refugee camp, and of an entire block in Gaza City.

Since the start of the war, at least 15,523 people have been killed and more than 41,000 others wounded, according to the latest figures issued Sunday by Gaza's health ministry.

The White House believes Israel was "making an effort" to minimize civilian deaths, National Security Council spokesman John Kirby told US media.

"We believe they have been receptive to our messages here of trying to minimalize civilian casualties," he said, including by publishing online a map of places where Gazans could go to find safety.

Israel 'eliminates' Hamas militants 

In a summary of activity issued on Sunday, Israel's military said a drone strike had "eliminated" five Hamas militants.

In an additional statement, the army said "about 500" tunnel shafts of Hamas's underground array "have been destroyed" since the war began.

"Soldiers continue operations to destroy Hamas's underground network of tunnels," it said, where Israeli officials claim some of the Palestinian group's leaders have been hiding.

And "approximately 10,000 air strikes were carried out" in Gaza during the fighting, the army said.

At least 17 rocket salvo were fired from Gaza towards Israel on Sunday, the Israeli army said, adding that most were intercepted and only caused minor material damage.

More Gazans displaced 

In a new estimate, OCHA said about 1.8 million people -- roughly 75 percent of Gaza's population -- are internally displaced, up from an earlier figure of 1.7 million.

"However, obtaining an accurate count is challenging," OCHA said in a report.

Israel-Lebanon border tensions 

The Israeli military said its air and artillery forces struck in Lebanon in response to "a number of launches" across the border.

Lebanon's Iran-backed Hezbollah group, a Hamas ally, said it had launched at least five attacks including a guided missile strike on an Israeli "military vehicle".

Official Lebanese media said "enemy artillery shelling" and heavy bombardment hit border area villages, also reporting air strikes with at least one "enemy drone".

UK surveillance flights 

Britain's military will conduct surveillance flights over Gaza to help locate hostages still held by Hamas, London's defense ministry confirmed on the weekend.

"Surveillance aircraft will be unarmed, do not have a combat role, and will be tasked solely to locate hostages," the ministry said.

The flights will take place over the eastern Mediterranean, including above Israel and Gaza, it said.