Fresh airstrikes rocked Beirut's southern suburbs early Saturday, with residents reporting loud blasts and huge smoke plumes.
The Israeli military had ordered evacuations in parts of south Beirut hours before the attack.
This latest assault comes as part of a wider campaign that has forced over 1.2 million Lebanese to flee their homes.
Hamas-affiliated media reported on Saturday morning that Saeed Atallah, a leader of a Hamas armed wing, has been killed alongside three family members.
The reported deaths occurred in an Israeli strike on a Palestinian refugee camp in Tripoli, northern Lebanon.
Atallah led the al-Qassam brigades, one of Gaza's largest and best-equipped militias in recent years. The group was previously headed by Mohammed Deif, presumed dead since July. Deif had been wanted by the International Criminal Court for alleged war crimes and crimes against humanity, including murder, rape, and hostage-taking.
Thursday night saw intense bombardment reportedly targeting Hashem Safieddine, tipped to be Hezbollah's next leader after Hassan Nasrallah. Safieddine's fate remains unknown.
Israel said that it targeted Hezbollah's intelligence headquarters in Beirut on Thursday night and that it had killed about 250 fighters since the start of its ground operation in Lebanon this week.
The Israel Defence Forces (IDF) said that its forces had also struck Hezbollah targets near the Masnaa crossing, which is on a key road in the east used by people fleeing the violence. It claimed that the militia was using the road to smuggle weapons into Lebanon.
An air strike destroyed part of the road about 700 metres from the checkpoint and three miles from the Syria border, preventing cars from going any further.
More than 300,000 people have fled to Syria in the past 10 days, according to the Lebanese government, with 1.2 million civilians displaced from their homes as a result of the offensive.
Israel continued striking Beirut and the south of Lebanon yesterday, including near the Beirut-Rafic Hariri International Airport, which borders the Dahiyeh area, a Hezbollah stronghold.
The IDF said it targeted the intelligence headquarters of Hezbollah in the south of Beirut.
Reports suggested that Hashem Safieddine - who has been widely touted as the successor to Hassan Nasrallah, the Hezbollah leader assassinated last week - was targeted in the air attack.
The Axios website cited three Israeli officials as saying that Mr Safieddine, the head of Hezbollah's executive council, had been targeted in an underground bunker.
However, Mr Safieddine's fate was unclear last night. Lieutenant-Colonel Nadav Shoshani, a spokesman for the IDF, said that it was still assessing the damage caused by the air strikes on Thursday night.
Hezbollah has made no comment, but the strike follows recent assassinations of senior Hezbollah officials inBeirut, including Fuad Shukr, Ibrahim Aqil, Ibrahim Kobeissi, Mohammad Surur and Mr Nasrallah, the militia's powerful and charismatic secretary-general, who developed it into a significant political force in Lebanon and the most heavily armed non-state group in the world.
The IDF reported yesterday that it had "eliminated" the head of Hezbollah's communication networks, Mohammad Rashid Sakafi, in a "precise, intelligence-based strike".
"As part of his position, Sakafi invested significant efforts to develop communication capabilities between all of Hezbollah's units in order to maintain the flow of information throughout the terrorist organisation,"
