The U.N. Special Coordinator for Lebanon Joanna Wronecka is “deeply concerned by the gradual expansion in the exchange of fire across the Blue Line in scope, scale and intensity, which increases the risks of a broader conflagration and undermines Security Council Resolution 1701 (2006),” her office said in a statement. 

“She urges an immediate halt to this dangerous cycle of violence and return to a cessation of hostilities,” the statement said.

Hezbollah shelled a military base in Israel's Ga'aton with dozens of Katyusha rockets and launched a second attack with guided missiles on the Meron air control base in what it said were responses to Israeli attacks on southern Lebanese towns.

The Ga'aton base lies around nine kilometers from the border with Lebanon and the attack is the first to target it since the beginning of hostilities.

UNIFIL Head of Mission and Force Commander Aroldo Lázaro on Tuesday sounded the alarm that over the past days there has been “a concerning shift in the exchanges of fire” between Israel and Hezbollah.

“This conflict has already claimed too many lives and caused significant damage to houses and public infrastructure. It has jeopardized the livelihoods and changed the life of tens of thousands of civilians on both sides of the Blue Line. Yet we now see an expansion and intensification of strikes,” Lázaro said in a statement distributed by UNIFIL.

Israeli warplanes struck Tuesday southern towns deep inside Lebanon, including a town near Sidon, almost 30 kilometers from the nearest Israeli boundary.

The series of airstrikes came shortly after Hezbollah launched a salvo of rockets at the Israeli Meron air control base in retaliation for deadly Israeli strikes on east Lebanon.

Hezbollah's deputy leader Sheikh Naim Qassem has warned that the group has much more weapons to use if Israel expands the war.

"If the Israelis go too far, we will retaliate more. All what we have used until now in the fighting is the minimum of what we own," he said in a speech Monday in an apparent reference to Hezbollah's huge arsenal including precision-guided missiles and explosive drones.

Israeli strikes near the Hezbollah-dominated city of Baalbek killed two group members Monday, two security sources told AFP, in the first strikes on Lebanon's east since clashes began after the Gaza war.

"Two Hezbollah members were killed in the Israeli strikes near Baalbek," a security official told AFP, with another security source also confirming the toll.

An Israeli airstrike targeted Monday a car in the Tyre district town of Majadel, killing at least one person, local rescuers said, without providing further details.

Israeli airstrikes had targeted earlier on Monday other areas deep inside Lebanon including Bouday near the northeastern city of Baalbek and Iqlim al-Tuffah, after Hezbollah shot down a "large" Israeli drone there.

Lebanon will respond next week to a French proposal for halting the Israel-Hezbollah cross-border clashes, caretaker Foreign Minister Abdallah Bou Habib said on Monday.

Israeli Defense Minister Yoav Gallant has said that Israel would increase its strikes on Hezbollah even if a ceasefire is reached in the Gaza Strip.

“We are planning to increase the firepower against Hezbollah, which is unable to find replacements for the commanders we are eliminating,” Gallant said during a visit to the Israeli army’s Northern Command headquarters in Safad.

U.S. Ambassador Lisa Johnson has visited the new American Corner in Beirut for its official opening Saturday, the U.S. Embassy said Monday.

The American Corner offers, all free of charge, access to information about American culture and values, educational opportunities in the United States, English language training, life skills and cultural activities. These services are available to all Lebanese, regardless of background.