A spokesperson for the Israeli military said in a statement on X that Lebanese armed group Hezbollah was violating the ceasefire and that Israel would act against it, telling people to head north and west away from the towns.
The towns are north of the Litani River and the zone in southern Lebanon occupied by Israeli troops, who have continued military operations despite the ceasefire. The military said that it struck Hezbollah fighters, rocket launchers and a weapons depot.
"From our perspective, what obliges us is the security of Israel, the security of our soldiers, the security of our communities," Israeli Prime Minister Benjamin Netanyahu said at a cabinet meeting in Jerusalem on Sunday.
"We act vigorously according to the rules we agreed upon with the United States, and also, by the way, with Lebanon."
Hezbollah said it would not cease its attacks on Israeli troops inside Lebanon and on towns in northern Israel as long as Israel continued its "ceasefire violations."
The Iran-backed group added in a statement that it would not wait for diplomacy that has "proven ineffective" or rely on Lebanese authorities that had "failed to protect the country."
Earlier on Sunday, Hezbollah said it had attacked Israeli troops inside Lebanon as well as the rescue force that came to evacuate them. The Israeli military said one soldier was killed and six more were wounded.
The Israeli military said it had intercepted three drones before they crossed into Israeli territory on Sunday, after sirens sounded in northern Israel.
The US-mediated ceasefire, which started on April 16 and has been extended to mid-May, has brought a significant reduction in hostilities between Israel and Hezbollah, though both sides have continued to fire at each other, trading blame over breaches.
More than 2500 people have been killed in Israeli strikes since the most recent war between Hezbollah and Israel began on March 2, days after the U.S. and Israel launched strikes against Iran.
The toll includes 277 women, 177 children and 100 medics, according to Lebanon's health ministry.
The ministry does not otherwise distinguish between militants and civilians, and Hezbollah has not announced a total toll of its fighters.
The group has buried dozens of fighters in group funerals in recent days. Hezbollah attacks have killed two civilians in Israel while 16 Israeli soldiers have died in Lebanon since March 2, Israel says.
