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.
A Russian attack on Ukraine's southern Odesa region killed two people and injured three overnight, Ukraine's emergency service and a government official said on Monday.
Former Philippine President Rodrigo Duterte was "pivotal" in the murder of thousands of people during his rule, prosecutors at the International Criminal Court (ICC) said on Monday, as they pushed for his trial to go ahead.
Children across parts of the US Northeast will stay home on Monday as a powerful winter storm forced school closures and pushed offices and transit systems onto emergency schedules, with officials across the region warning of dangerous travel conditions.
A passenger bus plunged 200 metres (650 feet) from a mountainous road in west Nepal before dawn on Monday, killing 19 people including three foreign nationals.
Human rights are under assault worldwide, the United Nations chief warned on Monday, citing widespread abuses of international law and devastating civilian suffering in conflicts in Sudan, Gaza and Ukraine.