The Israel military said on Sunday that its fighter jets hit thousands of Hezbollah rocket launcher barrels in southern Lebanon that were aimed for immediate fire toward northern and central Israel.
More than 40 launch areas in Lebanon were struck during the early morning strikes, it said in a statement.
The Hezbollah group had earlier confirmed launching hundreds of rockets and drones against Israel in retaliation for the assassination of a senior commander in Beirut last month.
It said the barrage had completed "the first phase" of its response to the assassination of Fuad Shukr, but that the full response would take "some time".
Expectations of an escalation between the two sides had risen since a missile strike in the Israeli-occupied Golan Heights last month killed 12 youngsters, followed by the killing of Shukr in Beirut.
Foreign Minister Israel Katz said Israel would respond to developments on the ground but did not seek a full-scale war. Defence Minister Yoav Gallant said Israel would do whatever necessary to defend itself.
Gallant declared a state of emergency, and flights to and from Ben Gurion airport in Tel Aviv were suspended for around 90 minutes.
Meanwhile, Lebanon's state news agency said that an Israeli air strike on a car in the southern Lebanese town of Khiam on Sunday left one person dead.
US and Iran closing in on memorandum to end war, sources say
Trump defends higher ballroom costs, targets less than $400 million
Trump says operation to reopen Strait of Hormuz will be 'paused'
Ukraine says Russia violated ceasefire initiated by Kyiv
Hantavirus-hit cruise ship to head to Spain after being granted permission
