The Shia Islamist Hezbollah claims to have fired 200 rockets and explosive drones at Israeli outposts in the border area and at the Israeli-occupied Golan Heights.
Israel responds with airstrikes against southern Lebanon.
Sirens sounded in northern Israel at the border with Lebanon on Thursday morning.
According to the Israeli army, 17 alarms were triggered in several areas over 1.5 hours. Fires have broken out in places where rockets and drones have struck.
Israel's military, IDF, says it is carrying out airstrikes in southern Lebanon in response to this morning's rocket and drone attack against northern Israel.
The shelling takes place a day after an Israeli attack in Lebanon, which killed a high-ranking military leader within the Iran-backed Hezbollah.
According to the militia group, Thursday's rocket and drone attacks are a response to the "murder committed by the enemy".