Israeli Iron Dome air defense system fires to intercept a rocket fired from Lebanon in northern Israel, Friday. AP-Yonhap

Hezbollah pounded northern Israel with 140 rockets Friday, a day after the militant group's leader Hassan Nasrallah vowed to retaliate against Israel for a mass bombing attack , the Israeli military and the militant group said.

Israel's military said the rockets came in three waves Friday afternoon targeting sites along the ravaged border with Lebanon.

Following the attacks, the Israeli military said it had struck areas across southern Lebanon targeting Hezbollah infrastructure but did not provide details of damage.

Hezbollah said its attacks had targeted several sites along the border with Katyusha rockets, including multiple air defense bases as well as the headquarters of an Israeli armored brigade they said they'd struck for the first time.

The Israeli military said 120 missiles were launched at areas of the Golan Heights, Safed and the Upper Galilee, some of which were intercepted. Fire crews were working to extinguish blazes caused by pieces of debris that fell to the ground in several areas, the military said.

The military did not say whether any missiles had hit targets or caused any casualties.

Another 20 missiles were shot at the areas of Meron and Netua, and most fell in open areas, the military said, adding no injuries were reported.

Hezbollah said the rockets were in retaliation for Israeli strikes on villages and homes in southern Lebanon, not two days of attacks widely blamed on Israel that set off explosives in thousands of Hezbollah pagers and walkie-talkies.

Hezbollah and Israel have exchanged near-daily fire since Oct. 8, a day after the Israel-Hamas war's opening salvo, but Friday's rocket barrages were heavier than normal.

Nasrallah on Thursday vowed to keep up daily strikes on Israel despite this week's deadly sabotage of its members' communication devices, which he described as a “severe blow.”

At least 20 were killed in the attacks and thousands were wounded when pagers, walkie-talkies and other devices exploded in Lebanon on Tuesday and Wednesday.

The sophisticated attacks have heightened fears that the cross-border exchanges of fire will escalate into all-out war. Israel has neither confirmed nor denied involvement in the attacks.

In recent days, Israel has moved a powerful fighting force up to the northern border, officials have escalated their rhetoric, and the country's security Cabinet has designated the return of tens of thousands of displaced residents to their homes in northern Israel an official war goal.

Fighting in Gaza has slowed, but casualties continue to rise.

Overnight, Palestinian authorities said 15 people were killed in multiple Israeli attacks in the Gaza Strip.

Those included six people, including an unknown number of children, in an airstrike early Friday morning in Gaza City that hit a family home, Gaza's Civil Defense said. Another person was killed in Gaza City when a strike hit a group of people on a street.

Israel maintains it only targets militants and accuses Hamas and other armed groups of endangering civilians by operating in residential areas. The military, which rarely comments on individual strikes, had no immediate comment.

Gaza's Health Ministry says more than 41,000 Palestinians have been killed in the territory since Hamas' Oct. 7 attack. The ministry does not differentiate between fighters and civilians in its count but says a little over half of those killed were women and children.

Israel says it has killed over 17,000 militants, without providing evidence.

More than 95,000 people have also been wounded in Gaza since Oct. 7, the Health Ministry said.

The war has caused vast destruction and displaced about 90% of Gaza's population of 2.3 million. (AP)