Hezbollah fighter Mustafa Salman was killed in an Israeli drone strike on a motorbike in the Tyre district town of Qlaileh, the group and the National News Agency said.

Another person was wounded in the strike.

United Nations Special Coordinator for Lebanon Jeanine Hennis-Plasschaert has arrived in Israel for a three-day visit, her office said.

“Since assuming office last month, Hennis-Plasschaert has extensively engaged the Lebanese leadership and key interlocutors on ways to deescalate tensions across the Blue Line,” her office said in a statement.

British Prime Minister Keir Starmer has called on all sides to exercise "caution" on the border between Israel and Lebanon, in his first telephone conversation since he was elected with Israeli Prime Minister Benjamin Netanyahu.

Hezbollah says it has launched its "largest" air operation, sending explosive drones at a mountaintop Israeli military intelligence base in the annexed Golan Heights.

It is the latest incident among escalating cross-border exchanges of fire that have triggered global alarm.

Hezbollah chief Sayyed Hassan Nasrallah has congratulated Iranian president-elect Masoud Pezeshkian on his victory, emphasizing Tehran's role as a "strong" supporter of regional "resistance" groups.

In a letter circulated on the Iran-backed group's social media channels, Nasrallah congratulated Pezeshkian on his "blessed election" by the Iranian people.

Hezbollah on Sunday fired rockets at an area deep in north Israel after an Israeli airstrike Saturday killed one of its operatives near the eastern city of Baalbek.

In a statement, the group said it launched dozens of Katyusha rockets at the Nimra military base west of Tiberias in response to the assassination near Baalbek. It described Nimra as "one of the main bases in the northern region" of Israel.

Hezbollah said Saturday that it launched suicide drones at an Israeli artillery position in Beit Hillel that had targeted Lebanese villages and civilians on Friday.

Hamas has said in a statement that its Doha-based top political leader, Ismail Haniyeh, has received Mohammed Takkoush, the head of Lebanon's al-Jamaa al-Islamiya, or the Islamic Group, a Sunni Muslim political and armed group in Lebanon that has been fighting against Israeli forces alongside Hezbollah.

The two Lebanese groups have been part of a “support front” that has maintained low-level clashes with Israeli forces with the aim of pulling them away from Gaza to ease the pressure on Hamas. In recent weeks, however, there have been increasing fears of a full-blown war on the Lebanon-Israel front.

The United Nations has warned that the increasing intensity of exchanges between Hezbollah and Israel “heightens the risk of a full-scale war.”

“Escalation can and must be avoided,” U.N. spokesman Stephane Dujarric said.

Hezbollah deputy chief Sheikh Naim Qassem has reassured that there will be no broad Israeli war on Lebanon in the near future.

“The possibilities of expanding the war are absent in the near future,” Qassem said in an interview with Russia’s Sputnik radio station.