Israeli strikes killed dozens in Gaza Sunday, the civil defense there said, and also hit a central Beirut district where a Lebanese source reported the death of Hezbollah's spokesman in one raid.

Israel has been fighting on two fronts since September, intensifying attacks on Lebanon's Iran-backed Hezbollah after nearly a year of cross-border clashes alongside its war on Hamas in the Gaza Strip.

A Lebanese security source said Hezbollah spokesman Mohammed Afif was killed in a strike on Beirut's Ras al-Nabaa district, one of relatively few attacks outside the group's strongholds. Israel's military declined to comment.

A year after the Gaza war was triggered by Hamas's unprecedented 7 October attacks, Israel launched a major assault in the north of the Palestinian territory which it said was meant to stop militants from regrouping there.

In the latest violence in besieged Gaza, the civil defense agency said Israeli air raids killed at least 46 people.

The deadliest strike, in the middle of the night in Beit Lahia in the north, killed 26 people, including women and children, and left at least 59 others buried under the rubble, civil defense spokesman Mahmud Bassal said.

"We heard the Israeli strike, and the whole area was shaking," said Jaber Ghabayen, whose family lived in the razed building.

"I was at a relatives' place, and we all thought that death was near," he told AFP.

Bassal said three separate attacks on refugee camps in central Gaza killed 15 people, and an Israeli drone strike on the southern city of Rafah killed five.

Hamas-run Gaza's health ministry on Sunday said the overall death toll in more than 13 months of war had reached 43,846.

The majority of the dead are civilians, according to ministry figures, which the United Nations considers reliable.

The 7 October, 2023 attack on southern Israel that sparked the war resulted in the deaths of 1,206 people, mostly civilians, according to an AFP tally of Israeli official figures.

Hezbollah official killed

On Israel's second front in the north, the Lebanese security source, speaking on condition of anonymity, said Hezbollah's Afif was killed in a strike on a central Beirut building which houses the office of the Lebanese branch of Syria's ruling Baath party.

Ali Hijazi, secretary-general of the Lebanese branch, "confirmed the death of Hezbollah media official" Afif, the official National News Agency (NNA) reported.

Lebanese state media earlier said the Israeli strike on Ras al-Nabaa district killed at least one person and wounded three.

Previous strikes claimed by Israel have killed senior Hezbollah officials, including its leader Hassan Nasrallah in late September.

AFPTV footage showed several strikes hit Hezbollah's south Beirut stronghold earlier, after the Israeli military warned people to evacuate.

Columns of smoke rose over the southern suburbs, where Lebanon's only international airport is located.

One raid "completely destroyed a 12-storey residential building" in the Chiyah district, the NNA said.

Further south, the NNA reported seven strikes on Jibsheet village in less than two hours, with more attacks on villages closer to the border with Israel.

The Israeli army said about 20 projectiles were seen crossing from Lebanon into Israel on Sunday, and that some were intercepted.

The UN force in Lebanon said in a statement peacekeepers were fired upon around 40 times on Saturday, probably by "non-state actor" individuals who tried to prevent a patrol from passing in the south. No injuries were reported.

Israel has escalated its bombing of Lebanon since September 23 and has since sent in ground troops, following almost a year of limited exchanges of fire begun by Hezbollah militants in support of Hamas in Gaza.