Hamas militants have used a bulldozer to open new passages through the border fence between Gaza and Egypt after Egyptian troops tried to close off the area.
Hundreds of Palestinians, who had been chanting pro-Hamas slogans while waiting to go into Egypt to stock up on goods, seized the opportunity and crossed the border on foot, defying Egypt's deadline for everyone to go home.
Gunfire could be heard as thousands of Palestinian onlookers cheered on the militants as they rammed the chain-link and barbed-wire fence at the crossing near Rafah in southern Gaza.
Security forces used electric batons to push back those trying to get into Egypt and to herd others back into Gaza. Egyptian armoured vehicles later arrived with coils of barbed wire in order to reseal numerous minor border breaches.
Police earlier announced by loudspeaker in towns near the border that the frontier would be closed from this afternoon, with an unknown number of Palestinians still in Egypt.
Ten of thousands of people have crossed the border in the past three days after militants blew a hole in the border fence in the divided frontier town of Rafah.
A security source said the deadline was intended to give Gazans who have crossed over since Tuesday sufficient time to return home.
The announcements were made both on the Egyptian side of Rafah and in the North Sinai provincial capital of El-Arish further west.
Israeli Prime Minister Ehud Olmert's government last week blocked fuel and aid shipments to Gaza amid an explosion of violence which has seen 45 people killed in Israeli raids.
The US, Israel's staunchest ally, insisted the blockade was an act of self-defence but many in the international community have protested at what they term 'collective punishment.'
The border wall was destroyed by militants three days ago as the humanitarian situation in Gaza worsened.
UN said yesterday that at least 700,000 Gazans had flooded over the border into Egypt seeking food and supplies.
