The sources identified the commander who was killed on Tuesday as Ibrahim Qubaisi. The attack, in which six people were killed, dealt another blow to the Iran-backed group which has faced a series of setbacks at the hands of Israel over the past week.
The relentless pressure on Hezbollah has increased fears that nearly a year of conflict will explode into another all-out war and destabilise the Middle East, where a conflict between Israel and Hezbollah's ally Hamas is already raging in Gaza.
At least 558 are dead and more than 1835 injured following air strikes in southern Lebanon. (EPA PHOTO)
Israel struck the Hezbollah-controlled area of the Lebanese capital for a second consecutive day after mounting a new wave of air strikes on targets in Lebanon,
After nearly 12 months of war against the Palestinian militant group Hamas in Gaza on its southern border, Israel is shifting its focus to the northern frontier, where Hezbollah has been firing rockets into Israel in support of Hamas, which is also backed by Iran.
The health ministry gave an initial toll of six dead and 15 wounded in the Beirut strike.
The Israeli military carried out air strikes against Hezbollah on Monday which Lebanese authorities said killed more than 500 people. The air strike hit a building in the usually busy Ghobeiry neighbourhood in Beirut. One of the security sources shared a photo showing damage to the top floor of a five-storey building.
Israel's military chief said earlier that attacks on Hezbollah would be accelerated.
"The situation requires continued, intense action in all arenas," said Military Chief of General Staff Herzi Halevi after holding a security assessment.
Residents check the site of an Israeli air strike in Beirut's southern suburbs. (AP PHOTO)
Lebanese authorities said 558 people had been killed, including 50 children and 94 women, in Israel's air strikes on Monday. A further 1835 were wounded, they said, and tens of thousands more have fled for safety.
The casualty tolls and the charge from the most powerful and advanced military in the Middle East has spread panic in Lebanon, which suffered from devastating destruction when Israel and Hezbollah fought in 2006.
"We are waiting for victory, God willing, because as long as we have a neighbour like Israel, we can't sleep safely," said Beirut resident Hassan Omar.
Afif Ibrahim, a taxi driver from southern Lebanon, was defiant.
"They (Israel) want us (Lebanese) to kneel, but we kneel only to God in our prayers; we bow our heads to no one but God," he said.
Calls for diplomacy are growing as the conflict worsens, with UN human rights chief Volker Turk urging all states and actors with influence to avert further escalation in Lebanon.
"I believe that we can still find a path forward to get de-escalation between Israel and across that northern border between Israel and Lebanon and bring about a diplomatic solution that allows people to return to their home," White House national security adviser Jake Sullivan told MSNBC.
Tensions rose after the recent explosions of pagers intended for use by Hezbollah across Lebanon. (EPA PHOTO)
The fighting has raised fears that the United States, Israel's close ally, and regional power Iran, which has proxies across the Middle East - Hezbollah, Yemen's Houthis and armed groups in Iraq - will be sucked into a wider war.
Hezbollah last week suffered heavy losses when thousands of pagers and walkie-talkies used by its members exploded in the worst security breach in its history.
The operation was widely attributed to Israel, which has a long history of sophisticated attacks on foreign soil. It has not confirmed or denied responsibility.Â
Israel's intelligence and technological prowess has given it a strong edge in both Lebanon and Gaza.
But Hezbollah has proven resilient during decades of hostilities with Israel, challenging superior firepower.
The group, which was founded by Iran's Revolutionary Guards in 1982 to counter an Israeli invasion of Lebanon, is a more formidable enemy than Hamas.
