Four people were wounded by Israeli air strikes near Lebanon's eastern city of Baalbek overnight, one of which hit a two-storey building, an AFP correspondent said on Sunday.
Israel and Hezbollah have been exchanging near-daily cross-border fire since the deadly Gaza war , which has killed more than 32,000 Palestinians, erupted in October.
But fears have surged of an all-out conflict in past weeks, with Israel launching air strikes deeper into Lebanese territory, targeting the Baalbek area - a Hezbollah stronghold - several times.
The Israeli military said in a statement that fighter jets "struck a Hezbollah manufacturing site containing weapons in the area of Baalbek".
The AFP correspondent said the Israeli strikes targeted a Hezbollah centre that had been deserted for some time, wounding four residents in nearby buildings.
"The Israeli air force fired five missiles at a two-storey inhabited building in Al-Osseira, on the outskirts of Baalbek," he said.
Hezbollah said it fired "more than 60 Katyusha-type rockets" at two Israeli military positions in the occupied Golan Heights in response to the Israeli strikes.
The strike at Al-Osseira, some 100 kilometres (62 miles) from the Israeli-Lebanese border, ended a period of relative calm that had lasted around 10 days.
Hezbollah began clashing with Israeli forces on October 8, a day after the surprise Hamas attack on southern Israel which began the current Gaza war. It said on Saturday it had carried out several more strikes.
It says it will only end its attacks on Israel if there is a ceasefire in Gaza.
Israeli Defence Minister Yoav Gallant warned in February that a possible truce in Gaza would not affect Israel's "objective" of pushing Hezbollah back from its northern border, by force or diplomacy.
At least 323 people have been killed in Lebanon, most of them Hezbollah fighters, but also at least 56 civilians including elderly women and children, according to an AFP count.
The exchange of fire, which was initially confined to areas close to the border, has also displaced tens of thousands in southern Lebanon.
