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 Hassan Nasrallah on Friday.

Lebanon's health ministry reported at least 105 people killed in Israeli strikes on Sunday, with 359 people wounded.

Monday's drone attack targeted an apartment belonging to two members of the Lebanese Islamist group Jamaa Islamiya in Kola district, the security source said.

It was the first strike within the city's walls since the October 7 Hamas attack on Israel last year.

"At least four people were killed in an Israeli drone strike targeting a flat belonging to Jamaa Islamiya in Beirut's inner city," according to the Lebanese source.

The Popular Front for the Liberation of Palestine (PFLP), a secular left-wing group, said three of its members were killed in the strike.

The group said in a statement that its military security chief Mohammad Abdel-Aal, military commander Imad Odeh, and Abdelrahman Abdel-Aal were killed.

Television footage showed the partially flattened floor of the building targeted by the strike, in the predominantly Sunni neighbourhood of Kola, near the road linking the capital to Beirut airport.

AFP journalists reported drones flying over the Lebanese capital throughout Sunday.

Hezbollah group has engaged in cross-border fire with Israel for almost a year and says it is acting in support of Hamas militants in Gaza, who attacked Israel on October 7, triggering the war in the Palestinian territory.

Israeli attacks have killed hundreds in Lebanon since last Monday, the deadliest day since the country's 1975-1990 civil war.

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

Barrot told Prime Minister Najib Mikati that Paris sought "an immediate halt" to Israeli strikes.

Saudi Arabia's foreign ministry issued a statement early Monday expressing "great concern" at the conflict in Lebanon, and calling for the country's "sovereignty and territorial integrity" to be respected.

Fear of 'conflagration'

Israeli aggression on Lebanon has sparked fears of an all-out war in the Middle East.

Pope Francis, asked about Israeli air strikes on civilians, said a country "goes beyond morality" when defence is not proportional to the attack.

Israeli military operations in Lebanon seek to downgrade Hezbollah's capacity to attack Israel, eliminate the group's military leadership and "clean" the border areas from fighters, an Israeli security official said Friday.

Israeli leaders say they want their citizens displaced from the north to be able to safely return.

Israel's military said dozens of its warplanes had also attacked targets of Iran-backed Huthi rebels in Yemen on Sunday.

Huthi media reports said the strikes had killed four people and wounded 33.

The Yemen raids came a day after the Huthis said they targeted Israel's Ben Gurion Airport with a missile, trying to hit it as Prime Minister Benjamin Netanyahu returned from New York.

Separately, Israel's military said the air strike that killed Nasrallah had "eliminated" another 20 Hezbollah members. Earlier strikes killed Nasrallah's right-hand man Fuad Shukr and the head of the elite Radwan Force, Ibrahim Aqil.

Israel also said Nabil Qaouq, a member of Hezbollah's central council, was killed in a strike on Saturday.

Hezbollah has yet to officially announce his death, but a source close to the group said Qaouq had been killed.

Seismic blow

Israeli bombardment has killed more than 700 people in a week, including 14 paramedics over a two-day period, according to Lebanon's health ministry.

Israel's military said late Sunday it had hit 120 Hezbollah targets.

Hezbollah said it had again fired rockets at the northern Israeli town of Safed.

Hezbollah is a powerful political, military and social force in Lebanon, but the killing of Nasrallah -- its figurehead who enjoyed cult status among supporters -- has dealt it a seismic blow.

Netanyahu said Israel had "settled the score" with his killing.

But in the northern Israeli town of Rosh Pina, Matan Sofer had mixed feelings. Sofer, 24, welcomed the "good news" of Nasrallah's death but wondered if "we risk it getting worse".

US President Joe Biden -- whose government is Israel's top arms supplier -- said Sunday a wider war "really has to be avoided".

Analysts told AFP Nasrallah's death leaves a bruised Hezbollah under pressure to respond.

For Tehran, his killing "has not altered the fact that Iran still does not want to get directly engaged" in the ongoing conflict, said Ali Vaez of the International Crisis Group.

Iran said a member of its Revolutionary Guards was also killed alongside Nasrallah.

'Largest displacement'

UN refugee chief Filippo Grandi said "well over 200,000 people are displaced inside Lebanon" and more than 50,000 have fled to neighbouring Syria.

Prime Minister Mikati said up to one million people may have been uprooted, in potentially the "largest displacement movement" in Lebanon's history.

In Gaza, the territory's civil defence agency said Israeli strikes Sunday killed several people.

Hamas's unprecedented October 7 attack on Israel resulted in the deaths of 1,205 people, mostly civilians, according to an AFP tally based on Israeli official figures that include hostages killed in captivity.

Of the 251 hostages seized by militants, 97 are still held in Gaza, including 33 the Israeli military says are dead.

Israel's retaliatory military offensive has killed at least 41,595 people in Gaza, most of them civilians, according to figures provided by the Hamas-run territory's health ministry. The UN has described the figures as reliable.