A senior commander from Hezbollah's elite force was killed in an Israeli strike on Beirut's southern suburbs on Wednesday, the first on the area in nearly a month, a source close to the group said.
At least 11 other people were killed in strikes across the south and east, according to the Lebanese health ministry.
Israeli Prime Minister Benjamin Netanyahu said his military had targeted "the commander of Hezbollah's Radwan force.”
The source close to Hezbollah told AFP on condition of anonymity that "Malek Ballout, the operations commander in the Radwan force" was killed.
Lebanon's state-run National News Agency had reported that "Israeli warplanes launched an attack, targeting Ghobeiri" in the southern suburbs, a Hezbollah stronghold.
An AFP correspondent saw a building covered in rubble following the strike, as people left the area with their belongings.
Many of the southern suburbs' residents had already left after Hezbollah drew Lebanon into the Middle East war in March, and have not returned despite the truce in force since April 17.
A Lebanese security source told AFP on condition of anonymity that the strike hit an apartment in which Radwan leaders were holding a meeting.
Beirut and its southern suburbs had been spared Israeli attacks since April 8, when massive Israeli strikes across the country killed more than 350 people.
Wednesday's attack came as US President Donald Trump said there was "a very good chance" of sealing a peace deal with Iran.
Israel has repeatedly bombed Lebanon, particularly the south, since the truce, with Hezbollah retaliating by launching attacks on Israeli troops.
The Israeli military said in a statement Thursday that an "explosive drone impact" wounded four soldiers -- one severely -- in southern Lebanon the previous day.
At least 11 people were killed in earlier Israeli strikes on southern and eastern Lebanon, the Lebanese health ministry said.
In Saksakiyeh, four people were killed and 33 wounded, including six children and four women.
The NNA also reported strikes across the south, including several on the town of Yater.
Israeli strikes on Lebanon have killed more than 2,700 people and displaced more than a million, particularly from southern and eastern Lebanon and Beirut's southern suburbs, since March 2.
World Health Organization chief Tedros Adhanom Ghebreyesus said on Wednesday it had "verified 152 attacks on healthcare that resulted in 103 deaths and 241 injuries.”
"These attacks have resulted in the closure of three hospitals and 41 primary health centers and caused damage to a further 16 hospitals."
The terms of the ceasefire allow Israel to act against "planned, imminent or ongoing attacks" by Hezbollah.
Visiting troops in southern Lebanon, where Israel has established a "yellow line,” Israeli army chief Eyal Zamir said they will "seize every opportunity to deepen the dismantling of Hezbollah and continue weakening it.”
