Palestinians inspect the damaged runway at the airport by the southern Gaza Strip town of Rafah. Israeli tank and bulldozers destroyed its runway early Friday.

The main road to Rafah was blocked by an Israeli tank, its turret pointed toward motorists who turned off and detoured on muddy tracks.

And in the Block O refugee neighborhood on the border with Egypt, residents were still digging through the crushed remains of dozens of cinderblock dwellings demolished by Israeli bulldozers on Thursday, a sweep that left hundreds of people homeless.

The Israeli measures against this town at the southern tip of the Gaza Strip were retaliation for the killing of four Israeli soldiers on Wednesday by Palestinian gunmen from a local refugee camp. The gunmen, who were also killed, had attacked an outpost in southern Israel a few miles from here.

The action against the airport struck a symbol of Palestinian aspirations for statehood. The Israeli bulldozers dug trenches in the runway, putting it out of commission.

The airport has been largely idle since a Palestinian uprising erupted more than 15 months ago, but repairs had begun on earlier damage to the runway on Dec. 4, when the Israelis bulldozed it in retaliation for suicide attacks, also bombing the airport's radar.

Fayez Zaidan, the head of the Palestinian Civil Aviation Authority, put the cost of repairs at $3 million. Inaugurated four years ago in a burst of fanfare and hope, the airport was abandoned today, except for a handful of guards.

At the Block O refugee neighborhood, residents wandered through a scene of devastation after the largest Israeli demolition operation since the start of the uprising. A United Nations offical said more than 50 homes had been destroyed and more than 500 people made homeless.

Climbing over piles of rubble and twisted steel, people collected pieces of wood and scavenged for other items they could still salvage or sell. A day after the demolitions, little was left of the contents of the ramshackle homes. A torn school book and notebooks were under the remains of one house, a crushed stroller and smashed sink were strewn a short distance away.

Residents said they had spent their first homeless night sleeping in the houses of neighbors and relatives.

Flanked by her two little sisters, one barefoot and the other in oversized borrowed shoes, Zeinat Abu Jazzar, 23, managed to keep her composure as she ticked off the meager belongings her family had lost.

Everything was gone, she said, including a supply of urgent medication her sisters had to take every week.

Then her voice broke.

"I can't find shelter since yesterday," she said, tears in her eyes. "Look at us, the clothes we're wearing are from the neighbors, my sister ran out of the house barefoot, we had to borrow shoes."

Boys scampering over the ruins whistled as an Israeli armored vehicle rumbled on the other side of a concrete wall separating the camp from a patrol road along the Egyptian border. As the boys gathered near the wall, shots rang out from an Israeli Army position on a neighboring building, sending the boys running for cover.

Gunfights between the soldiers and armed Palestinians firing from the refugee neighborhood have been a daily occurrence, and residents said today that they believed the Israelis were destroying the houses here as part of a deliberate plan to clear a strip of territory near the border fence.

The army said that the destroyed houses served as cover for the gunmen, and concealed tunnels through which weapons were smuggled into the area from Egypt.

"This is not the last time they will do this," said Atef Najjar, 42, as he stood in his house, where the walls of two rooms had been sheared off by the Israeli bulldozers. "I'm sure they will do it again."

Ibrahim Ghneim, 50, said he believed that his brother's home, where he had taken shelter overnight, was next. As the area had become a battle zone, he said, he had stuck it out, staying in his home while several neighbors had moved away.

"I was born here, this house was my kingdom, and now it's gone," Mr. Ghneim said, fingering a string of worry beads salvaged by his children from the rubble. "Where else can we go?"