Arab states sharply condemned Israel over the sharpest escalation in nearly a year of Israel-Hezbollah hostilities.

Israel said it hit about 1,300 Hezbollah sites in southern and eastern Lebanon in 24 hours, including a "targeted strike" in Beirut. A source close to Hezbollah said the strike in the Lebanese capital targeted Ali Karake, the group's third in command.

State media reported new raids in eastern Lebanon, while Hezbollah said it targeted five sites in Israel.

In the coastal Israeli city of Haifa, people were seen running for cover when air raid sirens sounded.

Health Minister Firass Abiad said "thousands of families" had been displaced.

"We sleep and wake up to bombardment... that's what our life has become," said Wafaa Ismail, 60, a housewife from the southern village of Zawtar.

World powers implored Israel and Hezbollah to pull back from the brink of all-out war, with the focus of violence shifting sharply from Israel's southern front with Gaza to its northern border with Lebanon.

Egypt -- a key mediator in the Gaza conflict -- urged the UN Security Council to intervene following Israel's "dangerous escalation", while the Iraqi appealed for an urgent meeting of Arab states on the sidelines of the UN General Assembly in New York.

'Most difficult week for Hezbollah'

Israeli army chief Herzi Halevi said the strikes hit combat infrastructure Hezbollah had been building for two decades.

Israeli Defence Minister Yoav Gallant called Monday "a significant peak" in the operation.

"This is the most difficult week for Hezbollah since its establishment -- the results speak for themselves," he said.

Prime Minister Benjamin Netanyahu said Israel was acting to change the "security balance" in the north by preempting threats.

Explosions near the ancient city of Baalbek in eastern Lebanon sent smoke billowing into the sky.

Hezbollah wave of rockets

Hezbollah, a powerful political and military force in Lebanon, has exchanged near-daily fire with Israel in support for its Palestinian ally Hamas.

Its deputy chief, Naim Qassem, said Sunday the group was in a "new phase, namely an open reckoning" with Israel and was ready for "all military possibilities".

He spoke after Hezbollah said it fired rockets at military sites near Haifa and later launched "dozens of rockets" at two Israeli bases "in response to the Israeli enemy's attacks on the south and the Bekaa".

The attack came after an Israeli strike on southern Beirut Friday killed its elite Radwan Force commander, Ibrahim Aqil, and coordinated communications device blasts that Hezbollah blamed on Israel killed 39 people and wounded almost 3,000 on Tuesday and Wednesday.

Since the cross-border exchanges between Israel and Hezbollah began in October, tens of thousands of people on both sides have fled their homes.

An Israeli military official, who cannot be further identified under military rules, said the operation seeks to "degrade threats" from Hezbollah, push them back from the border, and then to destroy infrastructure.

Lebanese Prime Minister Najib Mikati urged the United Nations and world powers to deter what he called Israel's "plan that aims to destroy Lebanese villages and towns".

Guterres 'gravely alarmed'

US President Joe Biden, whose country is Israel's main ally and weapons supplier, said his country was "working to de-escalate in a way that allows people to return home safely".

The Pentagon said it was sending a small number of additional US military personnel to the Middle East after thousands were deployed earlier alongside warships, fighter jets and air defence systems.

UN chief Antonio Guterres was "gravely alarmed" by civilian casualties in Lebanon his spokesman said.

The United Nations peacekeeping force in south Lebanon warned "any further escalation of this dangerous situation could have far-reaching and devastating consequences".

Iran's newly elected president, Masoud Pezeshkian, accused Israel of seeking "to create this wider conflict".

Since the beginning of the war on 7 October 2023, Israel has killed at least 41,455 people in Gaza, most of them civilians, according to figures provided by the the health ministry in Gaza.

*This story was edited by Ahram Online.