Israel strikes targets across the Gaza Strip.

The Israeli military struck targets from the air, ground and sea across the Gaza Strip overnight into Saturday, it said, as air-raid sirens warning of incoming rocket fire blared in Israeli communities near Gaza.

About a week into Israel’s new push in the south, the military said that much of the close-quarters fighting in its ground assault was taking place in Shajaiye, a neighborhood in northern Gaza that the Israeli military has called “a terrorist hotbed.”

The Israeli military said it had identified a number of fighters armed with anti-tank missiles approaching ground troops in the neighborhood and directed an Israeli helicopter strike there. It said it had also located and struck a tunnel shaft that was part of an extensive underground route in Shajaiye and located another tunnel shaft with an elevator and “numerous weapons.” The claims could not be independently confirmed.

Israel’s ground invasion, which began in northern Gaza in late October, has advanced south over the past week as intensive fighting spread through the enclave. Hundreds of thousands of Palestinians have fled northern Gaza for the south, and there are now few places for Gazans to go.

About 150,000 civilians are believed to remain in northern Gaza, according to the Israeli military. In recent days, the Biden administration has urged Israel to do more to limit harm to civilians, but some experts say they see no evidence that the military has moderated its tactics.

The Gaza Health Ministry, which is controlled by Hamas, said the Al Aqsa hospital in northern Gaza had received the bodies of 71 people who were killed, and that a further 160 wounded had arrived for treatment, in the past 24 hours. More than 15,000 people have been killed in Gaza since the war began, according to Gaza health officials. Another 6,000 or so are missing, officials say.

The Israeli military also said it had engaged with fighters “in the area of a school” in Shajaiye and found AK-47 rifles, grenades and ammunition inside classrooms. In Beit Hanoun, also in northern Gaza, the Israeli military said its troops had struck at Hamas fighters who shot at them from a mosque and from a school run by UNRWA, the United Nations agency that aids Palestinians.

The claim could not be independently confirmed, and UNRWA did not immediately respond to a request for comment. Israel has said that Hamas fighters are hiding out in hospitals, schools and other civilian areas in Gaza.

As the war continues, concerns have grown of a spillover of violence at Israel’s northern border, where the military has been exchanging sporadic fire with Hezbollah, the Iran-backed Lebanese militia. Early Saturday afternoon, a number of launches from Lebanon were fired toward northern Israel. The military said it had responded by targeting the source of the fire.

The strikes follow additional fire overnight, when the Israeli Air Force struck Hezbollah targets in Lebanon, including operational command-and-control centers, according to the army. There were also launches from Lebanon into Israel overnight, setting off aid-raid sirens warning of incoming rocket fire, and the Israeli army said it had responded by targeting the source of the fire.