Four Hezbollah fighters were killed overnight in southern Lebanon, the Iran-backed movement announced Thursday, in what Lebanese state media said were Israeli strikes on the border town of Naqoura.

The deaths, which according to a source close to the powerful militant group include a local Hezbollah leader, follow a strike on Beirut this week that killed a senior Hamas leader, raising regional tensions as war rages in Gaza.

Fears that Israel's war in Gaza could spiral across the Middle East have mounted after twin explosions ripped through an Iranian crowd, claiming at least 103 lives following a strike in Lebanon that killed Hamas's deputy leader.

More than 200 other people were wounded when the blasts about 15 minutes apart struck mourners commemorating slain Revolutionary Guards general Qasem Soleimani on the fourth anniversary of his killing in a United States drone strike, Iran's state media reported.

Near Israel's tense northern border with Lebanon, residents fear the killing of the deputy leader of Palestinian militant group Hamas in Beirut could spark a war with their neighbor.

During nearly three months of fighting between Israel and Hamas in Gaza, the Israeli army has also been exchanging cross-border fire with Lebanon's Hezbollah, which is allied with Hamas.

Germany has urged its citizens to leave Lebanon quickly, warning that an expansion of the Israel-Hamas war could not be ruled out after a drone strike in Beirut killed a senior Hamas leader.

"All German citizens, who are still in Lebanon, are asked to register on the ELEFAND crisis preparedness list and to leave the country as quickly as possible," wrote the German foreign ministry on X, formerly known as Twitter.

A high-level Lebanese security official has told AFP that Israel fired guided missiles from a warplane to kill Hamas number two Saleh al-Arouri in a Beirut suburb.

Lebanese authorities and Hamas accused Israel of killing Arouri in Beirut's southern suburbs on Tuesday, with Lebanese state media saying he died with six others in a drone strike.

Hezbollah chief Sayyed Hassan Nasrallah on Wednesday described Israel’s killing of Hamas deputy head Saleh al-Arouri in an airstrike in Hezbollah’s stronghold of Beirut’s southern suburbs as “a major and dangerous crime.”

“We cannot overlook it and the matter does not need a lot of talking. It will not remain without a response or punishment and the battlefield and days and nights will prove this,” Nasrallah said, in a televised address marking the third anniversary of the assassination of top Iranian general Qasem Soleimani and top Iraqi militant commander Abou Mahdi al-Muhandis.

A large hole is gaping in a building and debris litters the street in a southern Beirut suburb where a presumed Israeli strike killed the deputy leader of Palestinian militant group Hamas.

The day after loud blasts ripped through the district from the drone attack that killed Saleh al-Arouri, armed men of Hezbollah were standing guard in the area.

The Israeli artillery shelled Wednesday the outskirts of al-Labbouneh and al-Naqoura as Israeli media reported the launching of anti-tank missiles towards the upper Galilee. An Israeli drone later carried out a strike on the border town of Markaba.

Hezbollah said it has targeted the Zar'it barracks and the Jal al-Alam post. Hezbollah also targeted with a Burkan rocket a group of soldiers near al-Malkia post. The attack was a "direct hit", the group said.

Saleh al-Arouri, the senior Hamas official killed in a suspected Israeli strike in Lebanon, played a key role in building up the Palestinian group's military capabilities and its links with regional allies.

Arouri, 57, was one of the founders of the Ezzedine al-Qassam Brigades, the armed wing of Hamas, in the early 1990s.

Israeli war cabinet minister Benny Gantz says he has discussed with French President Emmanuel Macron “the imperative of an international diplomatic effort in Lebanon,” after Israel was accused of assassinating Hamas deputy head Saleh al-Arouri in a brazen drone strike in Beirut’s southern suburbs.

“I expressed my appreciation to President Macron for his commitment to Israel’s security, regional stability, and France’s important efforts to release the hostages held in Gaza,” Gantz said in an English-language post on the X platform.