Saturday's exchange was the first since Israel effectively abandoned a separate ceasefire in the Gaza Strip with Palestinian militant group Hamas, an ally of Hezbollah, both backed by Israel's arch-foe Iran.
The Israeli military said earlier it had intercepted three rockets launched from a Lebanese district about 6 km (4 miles) north of the border, the second cross-border launch since a U.S.-brokered ceasefire in November ended the fighting.
Israel's Army Radio said the military was returning artillery fire. Lebanon's state news agency said Israeli artillery hit two towns in southern Lebanon with airstrikes on three other towns closer to the border.
There were no reports of casualties from either side.