NEVE DEKALIM, Gaza Strip - Palestinian police today blocked off abandoned Jewish settlements and chased after scavengers in a first attempt to impose order after chaotic celebrations of Israel's pullout from Gaza. The overwhelmed forces were unable to halt looting of the area's prized greenhouses.

Egyptian guards, meanwhile, failed for a second straight day to control a rush across the Gaza-Egypt border, which was a formidable barrier when patrolled by Israel. With the Israelis gone, Gazans dug under walls and climbed over barriers to get to Egypt, where they stocked up on cheap cigarettes, medication and cheese. Egyptian forces on Monday fatally shot a Palestinian during the mad rush, witnesses said.

The chaos raised new questions about the ability of Palestinian forces to impose order in Gaza.

The greenhouses, left behind by Israel as part of a deal brokered by international mediators, are a centerpiece of Palestinian plans for rebuilding Gaza after 38 years of Israeli occupation. The Palestinian Authority hopes the high-tech greenhouses will provide jobs and export income for Gaza's shattered economy.

During a tour of Neve Dekalim, Palestinian Prime Minister Ahmed Qureia implored Palestinians to leave the structures intact, even as people scavenged through debris elsewhere in the settlement.

"These greenhouses are for the Palestinian people," he said. "We don't want anyone to touch or harm anything that can be useful for our people."

Just minutes away, crowds of looters in the Gadid settlement overwhelmed hundreds of guards trying to protect the greenhouses. Guards acknowledged that in many cases, they were unable to stop the looting.

"They are taking plastic sheeting, they are taking hoses, they are taking anything they can get their hands on," said Hamza Judeh, a Palestinian policeman.

He said about 80 percent of the greenhouses were still intact, but looters walked off with lighting fixtures, cables and wires. Many were undeterred by the police presence. Police said one man dropped his loot only after he was beaten by security forces.

Israel withdrew the last of its troops from Gaza early Monday, handing control of the coastal strip to the Palestinians. Celebrations frequently spun out of control, with Palestinians setting fire to debris and the few remaining buildings in empty settlements, and thousands of people rushing back and forth across the Egyptian border.

In an attempt to restore order, police early today banned cars from entering Neve Dekalim, once the largest Gaza settlement, and cordoned off the empty synagogue there, which had been set on fire a day earlier. Club-wielding police chased kids and urged people to stop scavenging through debris left behind by the Israelis.

"This is not right, and we are going to stop them from doing it," policeman Shafik Omran said as he looked at a man digging through a pile of garbage.

Despite the police efforts, Neve Dekalim was turned into a buzzing bazaar, with people haggling over bricks, scrap metal and other building materials they had collected. Similar scenes played out in other settlements.