Israel and Lebanon's Hezbollah on Sunday launched their heaviest exchange of fire after months of strikes and counterstrikes, raising fears of an all-out war that could potentially draw in the United States, Iran and militant groups across the region. Footage from Hezbollah-allied Lebanese news channel Al Mayadeen showed several large explosions in Zibqin, Lebanon. It came as Israel said around 100 warplanes launched airstrikes targeting thousands of rocket launchers across southern Lebanon, which it says was to thwart an imminent Hezbollah attack. Hezbollah then said it launched hundreds of rockets and drones aimed at military bases and missile defense positions in northern Israel and the Israeli-annexed Golan Heights. Hezbollah called the attack an initial response to the targeted killing of one of its founding members and top commanders, Fouad Shukur, in an Israeli airstrike in Beirut last month. It said the first stage of the attack was completed, which would allow it to launch attacks deeper into Israel. But it also said its military operations Sunday were concluded. It denied Israel's claims to have thwarted the attack. At least three people were killed, including a fighter with the Hezbollah-allied Amal group, and two other people were wounded in the strikes on Lebanon. Lt. Col. Nadav Shoshani, an Israeli military spokesman, said an initial assessment showed “very little damage” in Israel. Exclusive footage released by Al Mayadeen showed massive plumes of smoke from Israeli airstrikes in Zibqin in southern Lebanon. Al Mayadeen is politically allied with the Lebanese militant group Hezbollah.