GEOFF BENNETT: Welcome to the "News Hour."

For nearly a year, the U.S. has tried to prevent the war in Gaza from expanding.

But, tonight, there are new concerns of escalation after an Israeli airstrike killed a top Hezbollah commander following earlier unprecedented attacks on the militant group's communications network.

In all, more than 35 in Lebanon have died, thousands have been wounded, and tensions along the shared border are at their highest level in years.

Nick Schifrin reports.

NICK SCHIFRIN: Israel has promised a new phase of the war and is delivering it in Southern Beirut, where today an airstrike destroyed an entire residential building and Israel said it killed Ibrahim Aqil, commander of Hezbollah's special forces and about 10 of his soldiers.

Earlier this week, Israel's infiltration of Hezbollah's communication network turned Hezbollah walkie-talkies and pagers into bombs.

And Israel launched one of its largest bombing campaigns yet targeting Hezbollah rockets.

Thousands of Hezbollah rank and file are injured.

The group is in disorder and after today's strike without a member of its leadership council.

REAR ADM. DANIEL HAGARI, Spokesperson, Israeli Defense Forces: At the time of the strike, Aqil and the commanders of the Radwan forces were gathered underground under a residential building in the heart of the Dahiyeh in Beirut.

Hiding among Lebanese civilians, using them as human shields, they were in the middle of planning more terror attacks against Israeli civilians.

NICK SCHIFRIN: Aqil was wanted by the U.S. for the 1983 attacks on the Beirut embassy by Hezbollah's predecessor Islamic Jihad organization and the Marine Corps barracks attack that killed nearly 300.

Israel says it's trying to return 60,000 now empty cities in the north and does not want a regional escalation.

But Lebanese state media says today's attack also killed children, as did this week's attacks, adding to pressure on Hezbollah to escalate.

Just today, Hezbollah fired 200 rockets into Israel.

Despite this apparent momentum toward war, President Biden today held out hope for a cease-fire.

JOE BIDEN, President of the United States: We're going to keep at it until we get it done, but we have got a way to go.

NICK SCHIFRIN: A long way to go, as, tonight, the focus of the war appears to be shifting north.

For the "PBS News Hour," I'm Nick Schifrin.