Israeli warplanes bombed two electricity transformers in south Lebanon on Friday night, plunging the port city of Tyre into darkness, security sources said.
The attack came as Israel said it was expanding its ground operation in southern Lebanon.
An Israeli drone fired missiles into a convoy of refugees fleeing attacks in the southern town of Marjayoun, killing and wounding as many as 15 people, witnesses and security officials said.
The convoy, consisting of more than 100 civilian vehicles and those carrying a detachment of 350 Lebanese soldiers and police from the area around Marjayoun, was hit near Chtaura on the west side of the Bekaa Valley.
Two armored UN peacekeeping vehicles had led the convoy out of Marjayoun Friday afternoon, but it was not known if they were still accompanying it when the attack occurred.
Associated Press photographer Lutfallah Daher was with the convoy and said he saw the body of one dead man and many others wounded. The state-run National News Agency said at least four people were killed. Al-Jazeera television reported that the Lebanese Interior Minister Ahmed Fatfat said three people were killed and 7 wounded.
Marjayoun was taken by Israeli soldiers early Thursday and intense bombing and artillery fire has been reported in the region for the past 24 hours.
Security officials in the Bekaa said at least nine rockets were fired on the convoy. Hospital officials in the town of Job Jannine said they had received 25 casualties from the attack, although it was not immediately clear how many were fatalities.
Daher said there was a second attack on Red Cross and civil defense vehicles rushing the aid of the stricken convoy. It was not known, he said, if any rescuers were hurt.
Reuters contributed to this report