DEIR AL-BALAH, Gaza Strip >> Two Israeli airstrikes in the northern Gaza Strip on Tuesday killed at least 88 people, including dozens of women and children, health officials said, and the director of a hospital said life-threatening injuries were going untreated because a weekend raid by Israeli forces led to the detention of dozens of medics.

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

Concerns about not enough aid reaching Gaza were amplified Monday when Israeli lawmakers passed two laws to cut ties with the main U.N. agency distributing food, water and medicine, and to ban it from Israeli soil. Israel controls access to both Gaza and the occupied West Bank, and it was unclear how the agency known as 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 distributing aid in Gaza rely on its logistics and thousands of workers.

In Lebanon, the fighter 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, which has fired rockets into Israel since the start of the war in Gaza, 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.

The peacekeeping force, known as UNIFIL, said the rocket that struck its headquarters in Lebanon was “likely” fired by Hezbollah, and that it struck a vehicle workshop.

The Gaza Health Ministry’s emergency service said at least 70 people were killed and 23 were missing in the first of Tuesday’s strikes in the northern Gaza town of Beit Lahiya. More than half of the victims were women and children, the ministry said. A mother and her five children — some of them adults — and a second mother with six children, were among those killed in the attack on a five-story building, according to the emergency service.

A second strike on Beit Lahiya on Tuesday evening killed at least 18 people, according to the Health Ministry, which does not distinguish between civilians and fighters in its count.

The nearby Kamal Adwan Hospital was overwhelmed by a wave of wounded women and children, including many who needed urgent surgeries, according to its director, Dr. Hossam Abu Safiya. The Israeli military raided the hospital over the weekend, detaining dozens of medics it said were Hamas fighters.

“The situation is catastrophic in every sense of the word,” Safiya said, adding that the only remaining doctor at the hospital was a pediatrician. “The health care system has collapsed and needs an urgent international intervention.”

The Israeli military said it was investigating the first Beit Lahiya strike; it did not immediately comment on the second.

Israel’s recent operations in northern Gaza, focused in and around the Jabaliya refugee camp, have killed hundreds of people and driven tens of thousands from their homes.

The Israeli military has repeatedly struck shelters for displaced people in recent months. It says it carries out precise strikes targeting Palestinian fighters and tries to avoid harming civilians, but the strikes often kill women and children.

On Tuesday, Israel said four more of its soldiers were killed in the fighting in northern Gaza, bringing the toll since the start of the operation to 16, including a colonel.