An Egyptian policeman fired his rifle in the air on Friday when a group of Palestinians tried to make a new breach in the barrier, close to the main gap near the divided town of Rafah.
Palestinian police also shot in the air in a separate incident after an argument broke out between them and a group of people trying to break through into Egypt, said an Egyptian official who asked not to be named.
"It was just to frighten people and disperse them, and it didn't lead to any injuries," said the official.
The main Salaheddin Gate in the town which straddles the border remained open for the third straight day, despite Israeli complaints of anarchy and arms smuggling.
Flood of people
Border controls collapsed on Tuesday after Israeli troops pulled out of the area as part of their withdrawal from Gaza.
Israel now plans to move troops
to buffer the border with Egypt
Some 750 Egyptian border guards, deployed under a deal with Israel, were meant to hold the 12km line but many stepped aside in the face of an overwhelming flood of people.
The Egyptian authorities have said they intend to close the border and implement a border agreement with the Israelis when the Palestinians finish celebrating the Israeli departure.
But several deadlines have come and gone without the Egyptian border guards reimposing controls.
A senior Egyptian official said Egypt was reluctant to use force against Palestinians so soon after the Israelis had left.
Most of the travellers have been Palestinians buying cheap Egyptian goods or visiting relatives they have not seen for years, but Palestinian officials said on Thursday that some had brought guns into Gaza.
Israeli media reports said the Israeli army may move troops to buffer the long-quiet border with Egypt, alarmed that Palestinian fighters might find it easier to bring in weapons without an Israeli military presence on the frontier.
"(Israel) cannot accept a continued situation where the border will be entirely porous"
Israeli Foreign Minister
"(Israel) cannot accept a continued situation where the border will be entirely porous. What is happening in Gaza in recent days is complete anarchy," Israeli Foreign Minister Silvan Shalom told Army Radio.
On Thursday Palestinians from the resistance group Hamas punched a new hole in the border wall and hundreds more civilians streamed across.
Egyptian police have been patching up some of the gaps with razor wire and on the Gaza side Palestinian security have tried to stem the flow of people.
But an Egyptian security official said: "The large numbers of Palestinians coming in makes it hard to stop them by force without making the situation more complicated."