Palestinian Prime Minister Mahmoud Abbas canceled a visit to this northern Gaza town Wednesday after Israeli tanks and bulldozers again invaded it, with soldiers firing in the air and warning workers to evacuate factories. Abbas was scheduled to tour Beit Hanoun to survey damage from Israel's five-day invasion. Israeli troops, who pulled to the outskirts of the town Tuesday, had demolished 15 houses, uprooted thousands of trees and damaged the water and sewage systems, witnesses said. Despite the pullback, Israeli forces continued to hold territory inside the Gaza fence where Palestinian fighters often set up and fire handmade Qassam rockets at the Israeli town of Sderot, less than half a mile away. On Wednesday, 15 bulldozers rolled back into the industrial area of Beit Hanoun "and started a new wave of destruction," said Sofian Abu Zaida, chairman of the Palestinian liaison committee with Israel. "We were surprised that the army had come back in," Zaida said, adding that Abbas, also known as Abu Mazen, canceled his trip while Palestinian leaders made a call to the army to withdraw. Mohammed Dahlan, Abbas' new security chief, had been scheduled to accompany him on the visit. Dahlan decided to cancel the visit for security reasons, Zaida said. "The army presence is not only an obstacle and an affront to the Abu Mazen visit but an obstacle to any hope to achieve a lasting peace," Zaida said. The troop pullback Tuesday came despite a wave of Palestinian bombing attacks that killed 12 Israelis, hinting Israel might not undertake a large-scale punitive military operation that would further weaken Abbas, whom Israel sees as a crucial negotiating partner. The army said Wednesday that troops had never withdrawn completely from Beit Hanoun since the start of the raid and that operations were ongoing. **PHOTO CAPTION*** Israeli troops invade Bait Hanoun in Gaza Town, Wednesday, May 21, 2003 (Photo Reuters)