Lebanese civilians fled from the country's south and from Beirut's southern suburbs on Monday, seeking refuge in schools in Lebanon's capital following a new and deadly escalation between Israel and the Iran-allied Lebanese militant group Hezbollah.

Lebanon's Health Ministry reported at least 31 people were killed and 149 wounded in overnight strikes in the Beirut suburbs and southern Lebanon.

The Israeli military said it killed the head of Hezbollah's intelligence services, Hussein Moukalled, in a strike in Dahieh overnight.

"The IDF now confirms that in a precise strike in Beirut last night (Sunday), the terrorist Hussein Moukalled, who served as the head of Hezbollah's intelligence headquarters, has been eliminated," the army said in a statement on Monday.

The Israeli army warned Monday of imminent strikes on several regions in east and south Lebanon and Beirut's southern suburbs.

"You are located near facilities and assets belonging to Hezbollah, where the (Israeli military) will act against them forcefully in the near term," the army’s Arabic-language spokesperson, Lieutenant Colonel Ella Waweya, said on X.

Israeli Defense Minister Israel Katz warned Monday that Israel would send Hezbollah chief Naim Qassem to "the bottom of hell" like Iran's supreme leader Ayatollah Ali Khamenei, after an attack by the Lebanese armed group.

"We will strike Hezbollah hard, and Naim Qassem, chairman of the Hezbollah terrorist organization, will discover that whoever follows Khamenei's path ends up like Khamenei -- at the bottom of hell," Katz said during a visit to the Israeli air force operations center.

Lebanon's government has decided on an "immediate ban" of Iran-backed Hezbollah's military and security activity, Prime Minister Nawaf Salam said Monday, in an unprecedented move as Israel retaliated to rocket fire.

Lebanese Forces chief Samir Geagea on Monday warned that “the only thing that can save Lebanon from inevitable collapse” is for the Lebanese government to “declare Hezbollah an outlawed organization,” after the group fired rockets on Israel and the Israeli army began a wave of airstrikes on Lebanon.

“For the record: for twenty years, we left no stone unturned in our efforts to spare Lebanon this critical moment. But, alas … what we have reached today is neither surprising nor strange, given the nature of Hezbollah and its integral role within the Islamic Republic of Iran,” Geagea said in a post on X.

Israel's military said Monday there was no reason to launch a ground invasion of Lebanon "imminently" after an overnight attack from Hezbollah prompted Israel to retaliate with air strikes.

"There is nothing on the ground that constitutes going into ground invasion.. imminently," military spokesman Lieutenant Colonel Nadav Shoshani told journalists on whether Israel would send troops in Lebanon.

Israel's military said Monday it struck a senior Hezbollah operative in Beirut, with the defense minister saying the Lebanese group's chief Naim Qassem is "a marked target".

"A short while ago, the (Israeli military) precisely struck a senior Hezbollah terrorist in Beirut," the military said. AFPTV showed smoke rising from the southern Beirut district of Dahieh, a stronghold of Hezbollah.

Israel’s military chief Eyal Zamir said fighting against Lebanese militant group Hezbollah, which began early Monday, could take "many" more days.

"We have launched an offensive campaign against Hezbollah," Zamir said in a video shared by the military on Monday, hours after rocket fire claimed by Hezbollah prompted a wave of Israeli strikes on Lebanon. "We must be prepared for several days of fighting, many."

Prime Minister Nawaf Salam condemned rocket fire launched at Israel on Monday, as the Israeli military launched a series of strikes across Lebanon in response.

"Regardless of who is behind it, the rocket fire from southern Lebanon is an irresponsible and suspicious act that endangers Lebanon’s security and safety and gives Israel pretexts to continue its attacks on it," Salam said on X.