GAZA CITY, Gaza Strip ? Palestinian forces sealed off five major breaches along Gaza’s southern border Saturday, firing warning shots and clashing with stone-throwing crowds in their strongest effort yet to halt the chaotic flood of people in and out of Egypt since Israel withdrew from the area.

Throughout the day, crowds pelted Palestinian and Egyptian troops and managed to force their way across the border. But in contrast to previous days, the forces appeared determined to carry out Palestinian leader Mahmoud Abbas’ promise to have the border under control by early next week. Eight people were wounded.

The border mayhem and other unrest reflected the challenge that Abbas faces in asserting control after the Israeli withdrawal from Gaza.

Early Saturday, helmeted Palestinian riot police patrolled the border area, checking documents and bags carried by Palestinians returning from Egypt. Police also prevented Gazans from entering Egypt, witnesses said.

Palestinian bulldozers and cranes began closing holes in the border barriers, and Egyptian border guards rolled out barbed wire to keep trespassers out. By late Saturday, five of 14 holes in a border fence had been sealed with large concrete barriers.