Israel says it struck targets in Lebanon on Monday evening after vowing to retaliate for an attack by Hezbollah on a military post, with both sides accusing each other of violating last week's ceasefire.
In a post on X, the Israel Defense Forces (IDF) said more details of its strikes would be released later.
Hezbollah, the Iran-backed group, said it had fired mortars at the Israeli army position in an area occupied by Israel in response to earlier breaches of the ceasefire.
Israel said there were no injuries in Hezbollah's strikes on the Mt Dov area - a disputed region on the Israel-Lebanon border known internationally as Shebaa Farms.
Israeli Prime Minister Benjamin Netanyahu later described the Hezbollah attack as "a severe violation of the ceasefire", vowing that Israel would "respond forcefully".
Monday's violence seen as an indication of the fragility of the recently agreed truce, aimed at ending 13 months of conflict between Israel and Hezbollah.
Last week, the US and France said the agreement would “cease the fighting in Lebanon, and secure Israel from the threat of Hezbollah and other terrorist organisations operating from Lebanon”.
Hezbollah has been given 60 days to end its armed presence in southern Lebanon while Israeli forces must withdraw from the area over the same period.