RAFAH, Egypt: Egyptian guards with riot shields formed human chains along the Egypt-Gaza border on Friday, but were unable to stop hundreds of Palestinians from rushing into Egypt after a bulldozer wrecked another section of fence along the frontier.

Men in black clothing, some of them masked, stood atop the bulldozer as it knocked down a concrete slab under the watchful eyes of Egyptian forces on the other side who shot in the air in an attempt to hinder the flow of Gazans into Egypt.

Thousands of Palestinians, many of them carrying empty fuel canisters, managed to push through several openings, despite the presence of the Egyptians deployed nine rows deep in some places. At one point, guards aimed a water cannon above the heads of people, not at them, to keep them back.

Cranes were positioned next to the border, lifting crates of supplies over into Gaza.

The border was first breached on Wednesday, when Palestinian militants blew down large sections of the border wall. Since then, Egypt has allowed tens of thousands of Palestinians to go back and forth, but has rejected any suggestion of assuming responsibility for the crowded, impoverished territory.

In an interview published on Friday, President Hosni Mubarak called the situation in Gaza "unacceptable" and called on Israel to "lift its siege" and "solve the problem".

But as the chaotic border situation continued into the third day, it was increasingly clear that Egypt was unable to control its boundary with Gaza.

Earlier on Friday, Egyptian forces took up positions a few steps into Palestinian territory, using shields to protect themselves from some Gazans who climbed atop car roofs and threw stones at them. Witnesses said a photographer was lightly injured in the clash.

The influx included a gaggle of Palestinian women in finely embroidered dresses and fresh makeup, heading to relatives' weddings in Egypt they said had been hastily moved up to allow Gazan family members to attend.

Angry Egyptian officers watched as the bulldozer, commandeered by a masked man wearing black, knocked down the wall. One of the gunmen, believed to belong to the militant Hamas, joked while standing next to the bulldozer: "We are here to protect the Egyptians."

Sami Abu Zuhri, a Hamas spokesman, said Palestinians had to keep breaches open in the barrier "until the crossings are reopened", he said. "The gaps shouldn't be closed because they provide urgent assistance to the Palestinians."

Yousef Mohammed, 17, from Gaza, said he waited until Friday to make the trip because he was trying to get enough money together to shop in Egypt.

"They don't want us to go in," he said, pointing at the riot police.

The opening of the border, even if temporary, provided a significant popularity boost to Gaza's Hamas rulers, who can claim they successfully broke through the internationally supported Israeli closure that has deprived the coastal strip of normal trade and commerce for nearly two years.

Both Egypt and Israel restricted the movement of people and goods in and out of Gaza after Hamas won parliamentary elections in 2006, and further tightened the closure after Hamas seized control of the area by force last June.

Some Hamas gunmen fanned out along the Gaza side of the border on Friday, attempting to create order amid waves of Gaza residents approaching the area. It was the first time since the border fence was torn down that Hamas deployed uniformed men to deal with the chaos. The militant group has been using plainclothes agents to regulate the crowd.

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