CAIRO — This week saw a dizzying escalation in the nearly yearlong conflict between Israel and Lebanon’s Hezbollah. First came two days of exploding pagers and walkie-talkies used by Hezbollah - deadly attacks pinned on Israel that also maimed civilians around Lebanon.

Hezbollah’s leader vowed to retaliate, and on Friday the militant group launched a wave of rockets into northern Israel. Later in the day, the commander of Hezbollah’s most elite unit was killed in a strike in Beirut that killed dozens of others.

Many fear the events are the prelude to an all-out war between Israel and Hezbollah, the Iranian-backed Shiite group that is Lebanon’s most powerful armed force. A war threatens to bring devastation in Lebanon, heavy missile fire into Israeli cities and further destabilization to a region already shaken by the war in Gaza.

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During more than 11 months of exchanging fire over the Lebanese-Israeli border, both sides have repeatedly pulled back when the spiral of reprisals appeared on the verge of getting out of control, under heavy pressure from the U.S. and its allies. But in recent weeks, Israeli leaders have warned of a possible bigger military operation with the goal of stopping attacks from Lebanon to allow tens of thousands of Israelis displaced by the fighting to return to homes near the border.

Here are some things to know about the situation:

An Israeli airstrike Friday brought down a high-rise building in Beirut’s southern suburbs, a Shiite-majority area known as Dahiyeh where Hezbollah has a strong presence. At least 37 people were killed and more than 60 wounded, the deadliest Israeli strike in the Lebanese capital since the 2006 Israel-Hezbollah war.

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PHOTOS: What to know about the growing conflict between Israel and Lebanon's Hezbollah

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The Israeli military said the strike killed Ibrahim Akil, the commander of Hezbollah’s elite Radwan unit, as well as other top leaders of the unit. Hezbollah later confirmed that Akil was killed, a heavy blow to Hezbollah’s most effective fighters. Israel said Akil led the group’s campaign of rocket, drone and other fire into northern Israel.

The strike came after the shock of the electronic device bombings, in which hundreds of pagers and walkie-talkies used by Hezbollah detonated on Tuesday and Wednesday. At least 37 people were killed, including two children, and around 3,000 were wounded. Israel has neither confirmed nor denied its involvement.

The casualties included some fighters from the group, but many of the wounded were civilians connected to Hezbollah’s social branches. Analysts say the attack has little effect on Hezbollah’s manpower, but could disrupt its communications and force it to take tighter security measures.

Hezbollah fired 140 rockets into northern Israel on Friday, saying it was targeting military sites in retaliation for overnight Israeli strikes into southern Lebanon. There was no immediate report of casualties.

It was a continuation of the near daily drumbeat of exchanges over the border since the Israel-Hamas war began on Oct. 7. The exchanges have killed around 600 people in Lebanon – mostly fighters but including around 100 civilians - and about 50 soldiers and civilians in Israel. It has also forced tens of thousands of people to evacuate homes near the border in both Israel and Lebanon.

Hezbollah leader Hassan Nasrallah has promised retaliation for the electronic device bombings, raising fears of an escalation from the group. But Hezbollah also has proved wary of further stoking the crisis - it hasn’t carried out its vows of revenge after Israel’s killing of a top commander, Fouad Shukur, in July.

Hezbollah says its attacks against Israel are in support of Hamas. This week, Nasrallah said the barrages won’t end – and Israelis won’t be able to return to homes in the north – until Israel’s campaign in Gaza ends.

As fighting in Gaza has slowed, Israel has fortified forces along the border with Lebanon, including the arrival this week of a powerful army division that took part in some of the heaviest fighting in Gaza. It’s believed to include thousands of troops, including paratrooper infantry units and artillery and elite commando forces specially trained for operations behind enemy lines.

Defense Minister Yoav Gallant this week declared the start of a “new phase” of the war as Israel turns its focus toward Hezbollah.

“The center of gravity is shifting to the north by diverting resources and forces,” he said.

Israeli officials say they haven’t yet made an official decision to expand military operations against Hezbollah – and haven’t said publicly what those operations might be. This week, the head of Israel’s Northern Command was quoted in local media as advocating for a ground invasion of Lebanon.

A U.N.-brokered truce to their 2006 war called on Hezbollah to pull back 29 kilometers (18 miles) from the border, but it has refused to, accusing Israel of also failing to carry out some provisions. Israel is now demanding Hezbollah withdraw eight to 10 kilometers (five to six miles) from the border – the range of Hezbollah’s anti-tank guided missiles.

Israel and Hezbollah’s 2006 war was a devastating monthlong fight triggered when Hezbollah fighters kidnapped two Israeli soldiers in a cross-border raid.

In that war, Israel heavily bombarded southern Lebanon and Beirut and sent a ground invasion into the south. The strategy, later explained by Israeli commanders, was to inflict the maximum damage possible in towns and neighborhoods where Hezbollah operated to deter them from launching attacks.

But Israel could have a more ambitious and contentious goal this time: to seize a buffer zone in south Lebanon to push back Hezbollah fighters from the border. A fight to hold territory threatens a longer, even more destructive and destabilizing war – recalling Israel’s 1982-2000 occupation of southern Lebanon.

The fear is that it could turn out even worse than the 2006 war, which was traumatic enough for both sides to serve as a deterrent ever since.

The fighting then killed hundreds of Hezbollah fighters and an estimated 1,100 Lebanese civilians and left large swaths of the south and even parts of Beirut in ruins. More than 120 Israeli soldiers were killed and hundreds wounded. Hezbollah missile fire on Israeli cities brought the war to the public, killing dozens of civilians.

Now, Israel estimates that Hezbollah possesses about 150,000 rockets and missiles, some of which are precision-guided, putting the entire country within range of Hezbollah fire. Israel has beefed up air defenses, but it’s unclear whether it can defend against the intense barrages expected in a new war.

Israel has vowed it could turn all of southern Lebanon into a battle zone, saying Hezbollah has embedded rockets, weapons and forces along the border. And in the heightened rhetoric of the past months, Israeli politicians have spoken of inflicting the same damage in Lebanon that the military has wreaked in Gaza.