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.

Hezbollah targeted Friday several Israeli posts while the Israeli army bombed several towns in south Lebanon.

Israeli artillery shelled the outskirts of al-Hebbarieh and Rashaya al-Fokhar and warplanes raided the southern border town of Markaba injuring one person and the al-Rihan mountain in Iqlim al-Tuffah far away from the border.

Lebanese Forces leader Samir Geagea has again criticized Hezbollah for starting a war with Israel, at the expense of the Lebanese.

"There are 22 Arab states, why is Lebanon alone paying the price of what is happening in the region," Geagea asked in a televised interview on Thursday evening, adding that Hezbollah is hijacking the state's decisions. "Hezbollah is in Lebanon but its heart is with Iran," Geagea charged.