European Union foreign ministers called Monday for an immediate ceasefire between Israel and Hezbollah and have expressed support for U.N. peacekeepers in southern Lebanon.

“Arms should now be silenced, and the voice of diplomacy should speak and be heard by all,” EU foreign policy chief Josep Borrell told reporters after chairing an emergency meeting.

French Foreign Minister Jean-Noel Barrot met with Maronite Patriarch Beshara al-Rahi on Monday, stressing that the election of a president is a priority and emphasizing the importance of stopping the war between Israel and Hezbollah, a Bkirki spokesman said.

Barrot arrived in Lebanon on Sunday night, the first high-level foreign diplomat to visit since the Israeli air strikes intensified.

Saudi Arabia expressed its "great concern" at the conflict in Lebanon on Monday, calling for the country's "sovereignty and territorial integrity" to be respected.

A foreign ministry statement said: "the Kingdom of Saudi Arabia is following with great concern the developments taking place in the Republic of Lebanon."

Some 100,000 Lebanese and Syrian nationals have now fled to Syria from Lebanon amid Israeli airstrikes, the United Nations refugee chief said Monday.

"The number of people who have crossed into Syria from Lebanon fleeing Israeli airstrikes -- Lebanese and Syrian nationals -- has reached 100,000," Filippo Grandi said on X, adding that "the outflow continues".

Palestinian militant group Hamas said its leader in Lebanon was killed Monday in a strike on the country's south, as official media reported a strike on a Palestinian refugee camp.

"Fatah Sharif Abu al-Amine, the leader of Hamas... in Lebanon and member of the movement's leadership abroad" was killed in an air strike on his "home in the Al-Bass camp in south Lebanon", a Hamas statement said.

An Israeli strike on a Beirut apartment block killed four people on Monday, a Lebanese security source said, the first such raid on the heart of the city since the outbreak of the war in Gaza last year.

Israel has turned its focus from Gaza to Lebanon in recent days, carrying out strikes on Hezbollah targets that killed the Iran-backed group's leader Sayyed Hassan Nasrallah on Friday.

The Israeli military said on Sunday its air force had struck "dozens of Hezbollah terror targets" after carrying out "hundreds" of strikes on Friday and Saturday.

Lebanon's National News Agency reported a string of raids in and around the city of Baalbek in the east.

The Israeli strike that killed Hezbollah's leader Sayyed Hassan Nasrallah was a "measure of justice" for victims of a four-decade "reign of terror," U.S. President Joe Biden said.

The comments came after Hezbollah confirmed that Nasrallah, one of the group's founders, was killed in an Israeli airstrike in Beirut's southern suburbs the previous day.

Israeli Prime Minister Benjamin Netanyahu said that Israel had "settled the score" with the killing of Hezbollah chief Sayyed Hassan Nasrallah in an air strike in Dahiyeh.

"We settled the score with the one responsible for the murder of countless Israelis and many citizens of other countries, including hundreds of Americans and dozens of French," he said in his first statement since Nasrallah's death on Friday.

Pope Francis called for an immediate ceasefire in "martyred" Lebanon and the wider Middle East as he ended a three-day visit to Belgium.

"I call on all parties to immediately cease fire in Lebanon, Gaza, the rest of Palestine and Israel," the Argentinian pontiff, 87, told an open-air mass in Brussels, as Israel continued to target Hezbollah in Lebanon.