An Israeli strike on a car near the Syrian border killed a man Sunday, a security source said, after overnight fire wounded four people in Lebanon's east, a second security official said.
Israel and Hezbollah have been exchanging cross-border fire almost daily since the Gaza war between Israel and Hamas began last October.
But fears have surged of an all-out conflict in recent weeks with Israel launching air strikes deeper into eastern Lebanon, targeting Hezbollah strongholds in the Bekaa Valley area several times.
"Israeli aircraft targeted a vehicle in... Suwairi, killing its Syrian driver," a security source told AFP, requesting anonymity because of security concerns.
Earlier on Sunday, Lebanon's state-run National News Agency had said a strike on a vehicle in Suwairi, in Lebanon's east, injured the driver, before reporting that he had been killed.
The NNA said he had been delivering food in a car that belonged to a supermarket owner.
Images from the scene showed a burnt-out blue vehicle and a streak of blood on the ground nearby.
Overnight Saturday, Israeli jets struck a Hezbollah center that had been deserted for some time, the second security source told AFP. Four residents in nearby buildings had been wounded by the strikes, the source added.
The strike at al-Osseira, about 100 kilometers (62 miles) from the Israel-Lebanon border, ended a period of relative calm that had lasted around 10 days.
The Israeli military said in a statement that its fighter jets "struck a Hezbollah manufacturing site containing weapons in the area of Baalbek", referring to the main city in the Bekaa Valley.
The NNA had earlier reported three people injured in the Israeli strikes.
Later, 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 Israeli military also said "approximately 50 launches were identified from Lebanon toward northern Israel".
"A number of launches were intercepted while the rest fell in open areas," the military added.