State-run Lebanese media said Israel was conducting new raids across Lebanon's east Monday, hours after deadly strikes on the south and east, in the deadliest single day in nearly a year of cross-border clashes.

"Enemy raids targeted the mountain" areas in the Baalbek region and several towns and villages, the National News Agency said, adding that "the Israeli enemy" launched a strike on the town of Hermel.

The United Nations Special Coordinator for Lebanon, Jeanine Hennis-Plasschaert, begins an official visit to Israel today, Monday, her office said.

She is set to meet with senior Israeli officials to discuss recent developments, the office said in a statement.

Grand Ayatollah Ali Sistani, Shiite Islam's highest authority in Iraq, appealed Monday for "every possible effort" to end Israeli "aggression" against Lebanon.

Sistani called for "the exercise of every possible effort" to end this "barbaric aggression and to protect the Lebanese people."

A missile hit the al-Wardiyet area between the Jbeil district towns of Almat and Ehmej on Monday, as Israeli warplanes targeted Lebanon’s western mountain range.

Hezbollah said it targeted three sites in northern Israel including military production facilities in retaliation for intense Israeli strikes on south and east Lebanon.

"In response to the Israeli enemy attacks that targeted the south and Bekaa areas", Hezbollah fighters bombed two north Israel military positions as well as the "Rafael defense industry complexes" north of the city of Haifa, the group said in a statement.

An Israeli military official said Israel is focused on aerial operations and has no immediate plans for a ground operation.

The official, speaking on condition of anonymity in keeping with regulations, said more than 300 strikes on Lebanon's south and east on Monday are aimed at curbing Hezbollah's ability to launch more strikes into Israel.

The Kremlin on Monday said that the threat of escalation of attacks by Israel and Hezbollah was a matter of the utmost concern for Russia.

"The situation is swiftly deteriorating every day. Tension is growing, unpredictability is increasing. This is a matter of extreme concern for us," Kremlin spokesman Dmitry Peskov told journalists.

Caretaker Prime Minister Najib Mikati denounced a "destructive plan" amid intense Israeli strikes Monday on east and south Lebanon and as Israel's military said it attacked some 150 Hezbollah targets.

"The continuing Israeli aggression on Lebanon is a war of extermination in every sense of the word and a destructive plan that aims to destroy Lebanese villages and towns," Mikati told a cabinet meeting. He urged "the United Nations and the General Assembly and influential countries... to deter the (Israeli) aggression".

More than 200 people, including women and children, were killed Monday and more than 1000 were wounded as the Israeli military said it had targeted more than 300 Hezbollah sites in Lebanon in an unprecedented wave of air strikes.

"So far more than 300 Hezbollah sites have been targeted" since Monday morning, the military said in a statement. It earlier said more than 150 air strikes were carried out within just one hour, between 6:30 am and 7:30 am.

Hezbollah deputy chief Naim Qassem has said his group was in a "new phase" in its battle against Israel, which it has waged from across the Lebanese border since the Gaza war erupted.

"We have entered a new phase, namely an open reckoning" with Israel, Qassem said Sunday at the funeral ceremony of a senior Hezbollah commander killed in an Israeli strike on Friday.