A young Palestinian girl was shot and killed here Saturday as Israeli forces continued a five-day operation that has left 42 Palestinians dead, at least 60 houses demolished and one neighborhood sealed by a ring of tanks. The Israeli army said its forces had uncovered a tunnel used to smuggle weapons and that operations would continue.

Meanwhile in the West Bank, a bomber blew himself up at an Israeli army checkpoint near a Jewish settlement in the northern Jordan Valley, killing himself and injuring three other Palestinians and an Israeli soldier.

The Popular Front for the Liberation of Palestine claimed responsibility for the attack in a telephone call to the Associated Press, calling it a response to the Rafah incursion.

In Rafah, 3-year-old Rawan Mohammed Abu Zeid was shot as she and other children walked to a store to buy candy, relatives said.

The incident occurred on the same street that a U.N. delegation had visited moments earlier. The top official of the U.N. agency for Palestinian refugees was examining the ruins of houses when tank fire boomed from the end of the street. The U.N. group hustled out of the area. Witnesses said that about two minutes later, the girl was shot in the head.

An Israeli army spokesman, Capt. Jacob Dallal, said, however, "We do not know of fire in the area at the time of the incident."

The shooting took place in the Brazil neighborhood, where a days-long siege was lifted Friday, revealing at least a dozen blocks of half-destroyed houses and damaged infrastructure.

Dallal said Israeli tanks had avoided main roads in Brazil because they could be rigged with explosives. Instead, the tanks carved paths between houses, ripping out corners of buildings in their way.

A U.N. convoy carrying food, water and journalists was allowed to enter the nearby neighborhood of Tel Sultan, which remained sealed off by the Israeli army. Three tanks guarded the entrance to the area, one emitting choking black smoke and spinning its turrets.

After hours of delays, the U.N. convoy was permitted to approach the area. A private relief convoy was not allowed to enter, and a half-dozen trucks piled with blankets and food were stalled at the roadside.

The U.N. vehicles stopped several times near the entrance of the neighborhood, as they coordinated with the Israeli military to pass each segment of the path. In Tel Sultan, people gathered by the entrance, watching the slow advance of the convoy as they awaited food and water.

Soon children flooded out of the area, dancing and skipping to meet the U.N. vehicles. They climbed to the top of the food truck and gleefully dumped out boxes of powdered milk and flour, holding up bottles of water like emblems of victory glinting in the sun.

But some residents expressed anger that the aid had come so late and in such a small amount. Children began throwing rocks at two U.N. vehicles, smashing windows.

The wide main streets of the area were riven by huge gashes, which Dallal said were caused by a large iron claw fastened to the back of tanks to rip up the road to detect explosive devices.

Children played in the street with what appeared to be missiles.

Jad al Haq, 17, said that soldiers had partially destroyed his building in order to cut off the entrance and install snipers on the upper floors.

Just outside Tel Sultan, a bright blue U.N. sign was still erect, but buildings were damaged in a nearby U.N. project to house residents whose homes had been demolished.

"We feel outpaced by the rate of destruction," said Peter Hansen, the U.N. Relief and Works Agency's commissioner general. "As fast as we can build, the houses are destroyed faster."

An Israeli soldier scans nearby buildings for Palestinian gunmen in Rafah, near the border with Egypt. Israel pulled many troops and tanks out of the camp on Friday but continued the operation that has left 42 Palestinians dead.