An Israeli strike on a five-story building where displaced Palestinians were sheltering in the northern Gaza Strip killed at least 60 people early Tuesday, more than half of them women and children, Gaza’s Health Ministry said.

Israel has carried out more airstrikes and waged a bigger ground operation in northern Gaza in recent weeks, saying it is focused on rooting out pockets of Hamas militants that have regrouped there after more than a year of war. But the intense fighting in northern Gaza is raising alarm about the worsening humanitarian conditions for hundreds of thousands of Palestinians.

Concerns about a lack of aid reaching Gaza were amplified Monday when Israeli lawmakers passed two laws that cut ties with the main U.N. agency distributing food, water and medicine, and ban it from operating on Israeli soil. Israel controls access to both Gaza and the occupied West Bank, and it was unclear how the agency known by the acronym UNRWA would continue its work in either place.

“The humanitarian operation in Gaza, if that is unraveled, that is a disaster within a series of disasters and just doesn’t bear thinking about," said UNRWA spokesperson John Fowler. He said other U.N. agencies and international organizations rely on its logistics and thousands of workers to distribute aid in Gaza.

In Lebanon, the militant group Hezbollah said Tuesday it has chosen Sheikh Naim Kassem to succeed longtime leader Hassan Nasrallah, who was killed in an Israeli airstrike last month. Hezbollah vowed to continue with Nasrallah’s policies “until victory is achieved.”

A short while later, eight Austrian soldiers serving in the U.N. peacekeeping force in southern Lebanon were reported lightly injured in a midday missile strike. None of the soldiers needed emergency treatment, Austria's Defense Ministry spokesperson Michael Bauer wrote on the social network X.

UNIFIL, the international peacekeeping force, said the rocket that struck the base was “likely” fired by Hezbollah and that it struck a vehicle workshop.

Austrian Defense Minister Klaudia Tanner “condemns this attack in the strongest terms and calls on all sides immediately to cease combat operations in the surroundings of the U.N. mission’s positions,” Bauer wrote.

Strike in northern Gaza comes as Israel wages a major operation there

The Gaza Health Ministry's emergency service said at least 12 women and 20 children, including babies, were among the dead from Tuesday's strike in the northern Gaza town of Beit Lahiya. A mother and her five children — some of them adults — and a second mother with six children, were among the dead, according to an initial casualty list provided by the emergency service.

The toll from the strike was announced by Dr. Marwan al-Hams, director of the field hospitals’ department at the Health Ministry. He said another 17 people are missing.

Dr. Hossam Abu Safiya, the director of the nearby Kamal Adwan Hospital, said it was overwhelmed by the wave of wounded people from the strike. Israeli forces raided the medical facility over the weekend, detaining dozens of medics.

There was no immediate comment from the Israeli military regarding the strike in Beit Lahiya.

Israel’s latest major operation in northern Gaza, focused in and around the Jabaliya refugee camp, has killed hundreds of people and driven tens of thousands from their homes in another wave of mass displacement more than a year into the war in the tiny coastal territory. The Israeli military said on Tuesday it had killed 40 Hamas militants during recent operations in Jabaliya.

The Israeli military has repeatedly struck shelters for displaced people in recent months, saying it carried out precise strikes targeting Palestinian militants and tried to avoid harming civilians. The strikes have often killed women and children.

On Tuesday, the military said four more soldiers were killed in the fighting in northern Gaza, bringing the toll since the start of the operation to 16, including a colonel. The military says it has killed dozens of militants, without providing evidence, while Hamas does not publicize its losses.

Hezbollah's new leader has vowed to keep fighting Israel

Hezbollah said in a statement that its decision-making Shura Council elected Kassem, who had been Nasrallah's deputy leader for over three decades, as the new secretary-general.

Kassem, 71, a founding member of the militant group established following Israel's 1982 invasion of Lebanon, had been serving as acting leader. He has given several televised speeches vowing that Hezbollah will fight on despite a string of setbacks.

Hezbollah began firing rockets into Israel, drawing retaliation, after Hamas’ surprise attack out of Gaza on Oct. 7, 2023, triggered the war there. Iran, which backs both groups, has also directly traded fire with Israel, in April and then again this month.

The tensions with Hezbollah boiled over in September, as Israel unleashed a wave of heavy airstrikes and killed Nasrallah and most of his senior commanders. Israel launched a ground invasion into Lebanon at the start of October.

Hezbollah fired dozens of rockets into northern Israel on Tuesday, killing at least one person in the northern city of Maalot-Tarshiha, authorities said.

Israeli laws targeting UN agency could further restrict aid

UNRWA and other international groups continued to express outrage Tuesday about the Israeli parliament's decision to cut ties to the agency.

Israel says UNRWA has been infiltrated by Hamas and that the militant group siphons off aid and uses U.N. facilities to shield its activities, allegations denied by the U.N. agency.

Israeli government spokesperson David Mencer vowed that aid will continue to reach Gaza, as Israel plans to coordinate with aid organizations or other bodies within the U.N. “Ultimately, we will ensure that a more efficient replacement for UNRWA takes its role, not one which is infiltrated by the terrorist organization,” he said.

But aid groups have warned that there is no immediate replacement for UNRWA, which provides education, health care and emergency aid to millions of Palestinian refugees from the 1948 war surrounding Israel's creation and their descendants. Refugee families make up the majority of Gaza's population.

James Elder, a spokesperson for the U.N. children's agency, known as UNICEF, said the suspension of UNRWA's work “would likely see the collapse of the humanitarian system in Gaza."

He said that would impede deliveries of vaccines, winter clothes, hygiene kits, health kits, water, and ready-to-use therapeutic food to combat malnutrition.

Israel has sharply restricted aid to northern Gaza this month, prompting a warning from the United States that failure to facilitate greater humanitarian assistance could lead to a reduction in military aid.

The war in Gaza began when Hamas-led militants stormed into Israel on Oct. 7, 2023, killing some 1,200 people, mostly civilians, and abducting around 250. Some 100 hostages are still inside Gaza, a third of whom are believed to be dead.

Israel's retaliatory offensive has killed over 43,000 Palestinians, according to local health authorities. Around 90% of the population of 2.3 million have been displaced from their homes, often multiple times.