Israel fired tank rounds and artillery into southern Lebanon on Friday, its military said, in retaliation for a bomb that targeted Israeli soldiers patrolling the border.
No injuries were reported on either side.
The Israel-Lebanon border has been mostly quiet since Israel and the Lebanese militia Hezbollah fought an inconclusive war in 2006, even as civil war has raged in neighboring Syria over the past three years.
An Israeli military spokeswoman said the Israeli fire targeted "Hezbollah terror infrastructure in southern Lebanon" and that a hit was confirmed. A Lebanese security source said six mortars had struck the area.
Hezbollah has been helping President Bashar Assad in Syria fight rebels trying to topple his government.
Earlier this month Israel said its troops shot two Hezbollah gunmen who tried to plant a bomb further east near the fence between the Israeli-controlled Golan Heights and Syrian-held territory.
Reporting by Ari Rabinovitch and Alexander Dziadosz; Editing by Mark Trevelyan