The border, which was initially breached by Hamas militants, remained open for a fourth day, though Egyptian security forces blocked Gazans from driving beyond the border town of Rafah itself.
Egyptian border guards were now authorized to return fire if attacked, said a security official speaking on customary condition of anonymity on the Egyptian side of Rafah. Over the past two days, 38 Egyptian security forces have been injured - some seriously - after Palestinians hurled stones and shot at them at the border, Egypt's foreign minister said.
"These provocations cause us concern and our Palestinian brothers should note that the Egyptian decision to host them and ease their suffering should not result in threats to the lives of our sons in the Egyptian forces," Foreign Minister Ahmed Aboul Gheit told reporters after an emergency meeting in Cairo.
Egyptian troops have tried several times to stem the flow of hundreds of thousands of Palestinians through the breached border wall. On Friday, there were reports of Palestinians throwing stones and even shooting at the border guards and riot police.
Aboul Gheit said the decision to keep the border open stands, but Egyptian forces stopped Palestinian cars from proceeding any further into the Sinai Peninsula after Rafah, forcing thousands to walk to the coast town of El-Arish, located about 35 kilometers (21 miles) away from the border.
Armored personnel carriers blocking the roads out of Rafah turned traffic in the divided city into a honking gridlock as cars carrying Palestinians continued to drive over the border to visit relatives and buy food and livestock.
"Three days is not enough. Let us do our business before they reclose it, and nobody is doing us any favors here. We are paying a lot of money. We are not stealing anybody's property," said Amr, a middle aged Palestinian haggling over a mother camel and her daughter. He later bought the camels for $2,000 and led them back over the border.
Aboul Gheit renewed Egypt's invitation for Fatah and Hamas to resume dialogue, one day after President Hosni Mubarak offered to host talks between the leaders of the rival Palestinian factions, Fatah and Hamas.
Hamas said it would attend talks - but also urged Egypt to keep the borders open.
"We have announced our acceptance of President Mubarak's esteemed invitation without conditions and under Egyptian sponsorship," Moussa Abu Marzouk, deputy head of Hamas' political bureau, told The Associated Press in a telephone interview in Damascus.
Hamas hard-liner Sami Abu Zuhri told reporters that Hamas wants Egypt to take an "urgent and fast decision to open the crossing."
But Palestinian President Mahmoud Abbas stuck to his tough conditions for resuming contacts with Gaza's Hamas rulers, dimming prospects for Egypt's proposal to have the two Palestinian opponents come to Cairo.
Abbas insists he will only talk to Hamas if it retreats from its violent June takeover of Gaza, something Hamas is unlikely to do. Abbas renewed his offer of deploying his forces at the Gaza crossings, as a way of ending the closure of Gaza by Israel and Egypt.
Hamas engineered the border breach in an attempt to pressure Egypt to negotiation new border arrangements. Both Israel and Egypt have kept Gaza largely sealed in the past two years, especially since the violent Hamas takeover of the territory in June.
Egypt faces a dilemma over how to handle the border crisis. If it acts forcefully against the Gazans, it could anger its own people, who are sympathetic to the Palestinians' plight. But if it does nothing, it risks infiltration by Islamic militants.
Earlier Saturday, dozens of riot police formed human chains to block the two passages cut through the breached border, before once again giving up and allowing the cars to cross into the Egyptian side of the divided town. Authorities were making renewed efforts, however, to keep them out of the rest of the country.
Police set up extra checkpoints on the highway between Rafah and El Arish, turning Palestinians back toward the border but allowing other nationalities to pass through. Security troops were also sporadically deployed in open desert areas, trying to halt pedestrians from circumventing the checkpoints by walking along canals and dirt roads.
Some Palestinians were also inquiring about being smuggled to Cairo, saying Egyptian drivers have offered to take them for $1,000.
The streets of Egyptian Rafah continued to be jammed Saturday with people bargaining and buying goods including water, juice, gasoline, car batteries and carpets. Merchants conducted business in various currencies including Israeli shekels, Egyptian pounds and Jordanian dinars.
Other Gazans said their shopping was done and now it was time to enjoy a vacation.
"I bought everything we need, and now it's time to for me and the kids to do some family visitation and enjoy our time in Egypt," Abdul-Rahman Abu Shameh said after crossing the border.
Israel, meanwhile, has expressed growing concern about the possible influx of Palestinian militants into areas of Egypt that border Israel. The Israeli military announced Saturday that its troops were on heightened alert along the border with Egypt, and that an Israeli road and tourism sites in the area are temporarily closed. Israeli Prime Minister Ehud Olmert and Abbas were to meet in Jerusalem on Sunday, and the border crisis was sure to be discussed.
Israel withdrew its troops and settlers from the territory in 2005, but it still controls access to Gaza, including Gaza's airspace and coastline. Israel also provides the fuel needed to run Gaza's only power plant. It has recently withheld that fuel, causing severe power outages.
Around a thousand Israeli protesters gathered outside the Erez crossing between Israel and Gaza on Saturday to demand Israel lift its embargo on the impoverished, crowded coastal patch. Many waved Palestinian flags and wore the traditional black-and-white checkered scarf of Palestinians. Some Israelis wore stickers showing both the blue-and-white Israeli flag and the black-red-green and white Palestinian flag.
"You are not alone," a woman shouted from a loudspeaker, directing her words at Gaza residents, who live only a few hundred meters away.
Associated Press reporter Ibrahim Barzak contributed to this report from Rafah, Gaza.
By Omar Sinan and Ibrahim Barzak