Israeli troops pulled back from two neighborhoods in this sprawling Palestinian refugee camp Friday, leaving behind demolished homes, torn-up roads and flattened cars. They said the offensive — launched in search of arms-smuggling tunnels and militants — was not over.

Army spokeswoman Maj. Sharon Feingold said "dozens" of Palestinians, including senior suspected militants, had been detained and a local leader of the armed group Hamas (search) had been killed. The army said no tunnels had been found.

"The operation has not ended; we have redeployed forces and allowed residents to stock up on food," Feingold said.

At least 43 homes have been demolished and dozens more damaged in the camp since the offensive began Tuesday, municipal officials said. Thirty-nine Palestinians have been killed, including gunmen and eight demonstrators hit by a tank shell.

Feingold said five houses were demolished after they were used as cover by militants to attack troops. Other damage to homes and roads was caused by heavy military vehicles and Palestinian militant roadside bombs, the army said.

In the Brazil neighborhood, 25 houses were razed and streets were torn up, local officials said. In many cases, the facades of houses caved in or were shorn off after wide armored vehicles moved through the narrow alleys.

Residents picked through the rubble, retrieving mattresses, photo albums, shoes and clothing. A boy, oblivious to his surroundings, sat on the ground and scooped up sand with a broken toy bulldozer.

Israeli troops left behind leaflets in Arabic urging residents not to give shelter to armed men "who are using your homes and are hiding inside like rats."

Yacoub Othman, 55, who lives in the Brazil neighborhood, said he was hit by random fire in the leg as he walked downstairs in his home Wednesday.

"I tried to sterilize the wound with the little alcohol we had at home, but I couldn't even open the window and call on my neighbor to call for an ambulance because the snipers were right in front of us and the bulldozer was working in the street in front of us," said Othman. Doctors said Othman's wound became infected.

Reporters were still unable Friday to get into the hardest-hit neighborhood, Tel Sultan (search), which lost water and electricity for part of the Israeli offensive.

U.N. officials said several water trucks reached the area Friday, negotiating torn-up roads to bring fresh supplies to some of the neighborhood's 25,000 residents.

"It's quite wild — the trucks are being mobbed by the locals, who have been without supplies for such a long time," U.N. spokesman Johan Eriksson said.

Local officials said 10 homes were demolished in Tel Sultan and more damaged. Resident Fathi Abdel-Al, speaking by telephone, said he saw smoldering and charred cars, toppled electricity poles and sewage running in the streets.

Mohammed Jumaa, the owner of a zoo in Tel Sultan, said Israeli troops, backed by bulldozers, demolished cages and pens, killing some animals and setting dozens more free. A headless ostrich, dead chickens and a peacock littered the ground.

A tiger, some 55 African and American parrots, a variety of snakes and several raccoons and monkeys were missing, Jumaa said.

The Israeli army said it was checking the report.

Abdel Rahim Abu Jazer, 42, a teacher, searched for food and water for his children. "I hardly recognized my own street," he said. "I don't think an earthquake could do what the Israeli army did to this area."

A key objective of the offensive remains the widening of an Israeli patrol road between Rafah and the Egyptian border, which would make it more difficult for weapons smugglers to dig tunnels.

Widening the road also would require the demolition of dozens of Palestinian homes, a security official said on condition of anonymity. Palestinian officials estimate that hundreds of houses would be razed if the road is widened.

Israel's vice premier, Ehud Olmert (search), assured Secretary of State Colin Powell (search) in a meeting in Washington earlier this week that the buffer zone would not be widened, U.S. officials said. However, Israeli security officials said Friday the army is still pushing for an expansion of the zone by at least 300 yards.

Israeli Attorney General Meni Mazuz instructed the army on Thursday to come up with alternatives that cause less destruction. He said even the latest proposal would not hold up in local and international courts, officials said.

Israel launched "Operation Rainbow" on Tuesday, less than a week after 13 soldiers were killed by militants in the Gaza Strip.

The United States, European Union and United Nations have called for a halt to home demolitions. U.S. criticism was unusually sharp, and in a rare move the Bush administration allowed the passage of a stinging U.N. resolution condemning the operation.

Hundreds of Israeli peace activists protested the army operation at a Gaza crossing point Friday, chanting "Peace yes, confrontation no" and calling on soldiers to defy orders and join them.

Some 5,000 Palestinians chanted anti-Israeli slogans in Jabaliya refugee camp near Gaza City, a stronghold of the militant group Hamas, as Hamas and Islamic Jihad vans collected mattresses, blankets and other supplies for the residents of Rafah.

During more than three years of Palestinian-Israeli violence, Israeli forces have made dozens of forays into the Rafah camp to destroy weapons-smuggling tunnels. The Israeli military said 90 have been found and destroyed over the last three years. More than 11,000 Rafah residents have been left homeless by Israeli demolitions since 2000.

Israel charges that Palestinian militants have weapons stockpiled in the Egyptian Sinai desert across from Gaza, waiting to be smuggled in. Egypt has denied the charges.

On Thursday, an Israeli court convicted Palestinian uprising leader Marwan Barghouti of ordering shooting attacks that killed four Israelis and a Greek monk. The prosecution said it would ask for consecutive life sentences.

Barghouti, considered a possible successor to Yasser Arafat (search), is the highest-ranking Palestinian leader in Israeli custody. Barghouti said he does not recognize the right of the Israeli court to judge him. Sentencing is set for June 6.