An Israeli air strike targeted a senior Hezbollah commander in Beirut's southern suburbs late on Tuesday in what the Israeli military said was retaliation for a cross-border rocket attack three days before that killed 12 children and teenagers.
A loud blast was heard and a plume of smoke could be seen rising above the southern suburbs - a stronghold of the Iran-backed Lebanese armed group Hezbollah - at around 7:40 p.m. (1640 GMT), a Reuters witness said.
A senior Lebanese security source said a senior Hezbollah commander had been the target of the air strike and his fate remained unclear.
Lebanon's state-run national news agency said an Israeli air strike had targeted the area around Hezbollah's Shura Council in the Haret Hreik neighborhood of the capital.
Beirut has been on edge for days ahead of an anticipated Israeli attack in reprisal for the rocket strike on the Israeli-occupied Golan Heights on Saturday that killed the 12 youngsters in a football field in a Druze village.
Hezbollah has denied involvement in that attack.
In a statement, the Israeli military said it had conducted "a targeted strike in Beirut on the commander responsible for the murder of the children in Majdal Shams and the killing of numerous additional Israeli civilians". Details would follow.
Earlier on Tuesday, more rocket fire from south Lebanon killed a civilian in a kibbutz in northern Israel, medics said.
Shortly before the explosion in south Beirut, the Israeli military said 15 projectiles had been fired across the Lebanese border within the past few hours, with impacts in parts of the Upper Galilee region. No injuries were reported.
Israel's air force had just hit a Hezbollah observation post and "terror infrastructure" in south Lebanon, it added.
CONCERNS ABOUT ESCALATION
As diplomats sought to contain the fallout, US Defense Secretary Lloyd Austin said he did not believe a fight was inevitable between Hezbollah and Israel, though he remained concerned about the potential for escalation.
Hezbollah and Israel, which last fought each other in a major war in 2006, have been trading fire since the eruption of the Gaza war in October, after Hezbollah began firing at Israeli targets in what it says is solidarity with the Palestinians.
The hostilities have mostly been limited to the frontier region and both sides have previously indicated they do not seek a wider confrontation even as the conflict has prompted worry about the risk of a slide towards war.
In the latest exchanges of fire on Tuesday, the Israeli military said 10 rockets had been fired from Lebanon and one hit Kibbutz Hagoshrim, causing one casualty. Israel's ambulance service said the 30-year-old male died of shrapnel wounds.
Israel said it hit some 10 Hezbollah targets in south Lebanon overnight and killed one Hezbollah fighter - attacks which appeared to be in keeping with the pattern of the last nine months. Hezbollah confirmed one of its fighters was killed.
Meanwhile the United States said it will continue pursuing diplomacy to avert an escalation of the conflict between Israel and Hezbollah.
"We're continuing to work toward a diplomatic resolution that would allow Israeli and Lebanese civilians to return to their homes and live in peace and security. We certainly want to avoid any kind of escalation," deputy State Department spokesman Vedant Patel told a briefing.
