Beirut, Lebanon — Israel expanded its airstrikes on Iran-backed groups in Lebanon and beyond over the weekend, launching raids thousands of miles away on Yemen’s Houthi rebels. The Israeli attack on Houthi targets in the Yemeni port city of Hodeida came after months of U.S. and British strikes against the group – a joint response to the rebels’ regular rocket, drone and missile attacks on international military and commercial vessels in the Red Sea.

The Israeli strikes also came, however, amid growing concern that Israel’s nearly-year-long war with the Houthi’s ideological allies Hamas in the Gaza Strip and Hezbollah in Lebanon could spiral into a broad regional conflict, drawing in Iran and even the U.S. to back their respective allies.

Israel hit the Houthis just a couple days after it assassinated Hezbollah’s longtime leader Hassan Nasrallah with a massive airstrike on Friday.

After that strike, Israeli forces continued pounding purported Hezbollah and Hamas targets across Lebanon’s south and east all weekend, but the southern Beirut suburb of Dahiyeh, the Hezbollah stronghold where Nasrallah was killed along with another senior commander and two other high-ranking members of the group, has borne the brunt.

The well-armed group’s surviving deputy leader Naim Qassem vowed Monday that Hezbollah would carry on – despite its near decapitation via airstrikes, and before that exploding pagers and walkie talkies – “facing the Israeli enemy to support Gaza and Palestine.”

He accused the U.S. of offering Israel “limitless support” for Israel to carry out “massacres” in Lebanon and Gaza, and then claimed Hezbollah had fired even more weapons at Israel, and deep into the country, since Nasrallah was killed.

But Hezbollah’s incessant drone and rocket fire is virtually wiped out by Israel’s advanced air defenses before it reaches any targets. There have been civilians injured over the last couple weeks, but in Lebanon’s capital, entire residential buildings have been flattened.

CBS News went to see the aftermath of one Israeli strike Sunday on the edge of Dahiyeh. A five-storey-building was reduced to rubble. It was still smoldering as another massive boom reverberated in the distance, underscoring the unpredictable security situation for Lebanese civilians as Israel carries on, determined, it says, to push Hezbollah many miles away from its border to stop the cross-border attacks.

Israel has assassinated at least five Hezbollah commanders over the past week alone, and 19 in just a few months — dealing a major blow to the U.S.-designated terrorist group. Hezbollah ramped up its attacks on Israel a day after Israeli forces launched their first airstrikes on its Hamas allies, in immediate response to Hamas’ Oct. 7 massacre.

Hezbollah has acknowledged losing more than 30 operatives in recent weeks, including many of its senior leaders, but the ferocity and pace of the Israeli strikes in Lebanon has also taken a massive toll on Lebanese civilians. At least 1,000 people have been killed in just two weeks — 105 on Sunday alone.

According to Lebanon’s Prime Minister Najib Mikati, the strikes have displaced almost 1 million people from their homes, most of them fleeing southern Lebanon for Beirut of other locations further north.

Some of those displaced families — including many with young children — have come to Beirut’s iconic Blue Mosque, desperate to find safety. The place of worship has become a refuge for people who told CBS News they’d rather sleep in the courtyard’s surrounding the building, out in the open, than go back to their neighborhoods amid Israel’s bombardment.

Samar al-Attrash is among those who have found sanctuary outside the mosque. She fled her home in Dahiyeh with her husband and their three children, and little more than the clothes on their backs.

“We have nowhere to go to but here,” the mother told us. “We are very scared and we can’t go back to Dahiyeh at all until the situation gets better.”

“I told my kids it’s scary and that we can’t go home,” she said. “I’m only telling [them] a little at a time so I don’t traumatize them.”

President Biden reiterated his warning on Sunday that an all-out regional war must be avoided, but as he spoke, CBS News correspondent Chris Livesay and his team reported that tanks and armored vehicles were massing on the Israeli side of the country’s northern border with Lebanon. 

On Monday, Israeli Defense Minister Yoav Gallant paid another visit to Israeli troops waiting for orders near the border, telling them killing Nasrallah was, “an important step, but it is not the final one.”

“We will employ all of our capabilities,” Gallant told the Israeli troops, “and this includes you.”

It was the latest clear signal that Israel is preparing for some kind of ground operation in Lebanon — a move that has the potential to spark fighting even deadlier than anything seen since Oct. 7.

Despite the body blows dealt by Israel, Hezbollah’s deputy leader claimed Monday that the group’s “military capabilities are solid,” that it “will continue along the same path” it has been on for months – and that it is ready for a war with Israel.

contributed to this report.

Imtiaz Tyab

Imtiaz Tyab is a CBS News correspondent based in London and reports for all platforms, including the “CBS Evening News,” “CBS Mornings,” “CBS Sunday Morning” and CBS News 24/7. He has extensive experience reporting from major global flashpoints, including the Middle East and the war on terror.