BEIRUT — Israeli airstrikes hit central Beirut on Thursday evening, killing at least 18 people and wounding dozens, Lebanon’s Health Ministry said, the latest in Israel’s broadening campaign against Iran-backed Hezbollah militants in Lebanon.

The Health Ministry said the strikes badly damaged a residential building and caused another to collapse.

Even as attention has shifted to Israel’s war against Hezbollah in Lebanon and rising tensions with Iran, Israel has continued to strike at what it says are militant targets across the Gaza Strip.

An Israeli strike on a school sheltering displaced people in central Gaza killed at least 27 people on Thursday, Palestinian medical officials said. The Israeli military said it targeted Palestinian militants, but people sheltering there said the strike hit a meeting of aid workers.

Israeli strikes have been far more common in Beirut’s tightly packed southern suburbs, where Hezbollah bases many operations, but rare deeper inside the Lebanese capital.

There was no immediate statement from the Israeli military on the rare strikes inside Lebanon’s capital that rocked two different neighborhoods in the city’s west, sending smoke rising from the rubble of damaged buildings.

The fighting has boiled over into all-out war in recent weeks, with Israel carrying out waves of heavy strikes across Lebanon and launching a ground invasion in the nation’s south. Hezbollah has expanded its rocket fire to more populated areas deeper inside Israel, causing few casualties but disrupting daily life.

Farther south in Lebanon, the U.N. peacekeeping force said an Israeli tank fired on its headquarters in the town of Naqoura, hitting an observation tower and wounding two peacekeepers.

The attack drew widespread condemnation and prompted the Italian Defense Ministry to summon Israel’s ambassador in protest.

The Israeli military acknowledged opening fire at a U.N. base in southern Lebanon on Thursday and said it had ordered the peacekeepers to “remain in protected spaces.”

The U.N. peacekeeping mission known as UNIFIL said in a statement that its headquarters and nearby positions “have been repeatedly hit.”

It said the Israeli army also fired on a nearby bunker where peacekeepers were sheltering, damaging vehicles and a communication system. It said an Israeli drone was seen flying to the bunker’s entrance.

UNIFIL, which has more than 10,000 peacekeepers from dozens of countries, was created to oversee the withdrawal of Israeli troops from southern Lebanon after Israel’s 1978 invasion.

The United Nations expanded its mission following the 2006 war between Israel and Hezbollah, allowing peacekeepers to patrol a buffer zone set up along the border.

Israel accuses Hezbollah of establishing militant infrastructure along the border in violation of the U.N. Security Council resolution that ended the 2006 war. It has warned people to evacuate from dozens of communities in southern Lebanon, many of which are outside the buffer zone.

The European Union’s top diplomat, Josep Borrell, sharply condemned Israeli strikes that hit UNIFIL positions as “an inadmissible act, for which there is no justification.”

From Italy, which has about 1,000 soldiers deployed as part of UNIFIL, Prime Minister Giorgia Meloni said her government formally protested to Israeli authorities. Italian Defense Minister Guido Crosetto went further, claiming Israel deliberately targeted the UNIFIL base in southern Lebanon in strikes that “could constitute war crimes.”

Several other countries, including France and Jordan denounced the Israeli attacks.

The U.N. peacekeeping chief, Jean-Pierre Lacroix, said last week that peacekeepers would stay in their positions on Lebanon’s southern border despite Israel’s request to vacate areas before it launched its ground operation against Hezbollah. Crosetto endorsed that, saying that “the U.N. and Italy cannot accept orders from the Israeli government.”

Before the Beirut strikes, Lebanon’s crisis response unit said Israeli shellfire and airstrikes over the past 24 hours had killed 28 people and wounded 113, bringing the total to 2,169 killed and 10,212 people wounded in Lebanon since the war erupted last October. At least four people were killed Thursday in the eastern Bekaa Valley, Lebanese health authorities said.

Hezbollah attacks have killed 28 civilians in northern Israel since the war began, as well as 39 Israeli soldiers, including both in northern Israel since last October and in southern Lebanon since Israel’s invasion.

Israeli ground troops invaded southern Lebanon on Sept. 30 and have been battling the militants in deadly combat since.

Israel says the ground invasion, which has so far focused on a narrow strip along the border, is aimed at pushing the militants back so that tens of thousands of Israelis can return to their homes in the north. The fighting has displaced 1.2 million people in Lebanon.

Hezbollah began firing rockets into Israel on Oct. 8, 2023, in support of Iran-backed Hamas and the Palestinians, drawing Israeli airstrikes in retaliation.

Hezbollah kept up rocket fire into Israel on Thursday, setting off air raid sirens in parts of northern Israel. Several drones heading toward Israel were intercepted, the military said.