( dpa ) - Egypt set a 3 pm (1300 GMT) deadline Friday for hundreds of thousands of Palestinians to return to the Gaza Strip after they went on a two-day shopping spree in Egyptian cities near the border with Gaza to escape a tight Israeli blockade.
Egyptian security forces in full riot gear deployed along Egypt's border with the Gaza Strip during the morning set up a human chain to prevent any more Gazans from entering Egypt, witnesses said.
Scores of Gazans carrying sacks and boxes with goods, however, were allowed back into the Strip.
Several youths threw stones at the Egyptian guards in green camouflage, bullet-proof vests and helmets and armed with clubs and plastic shields. The guards sporadically used water canons and fired into the air to push back the crowds.
Megaphones on Egyptian security vehicles announced the deadline to Palestinians still present in the coastal city of al-Arish, south- west of Gaza, and in the Egyptian side of the divided border town of Rafah, al-Jazeera reported.
Meanwhile two Israeli airstrikes in the southern Gaza Strip town of Rafah early Friday killed four militants of the radical Islamic Hamas movement, Palestinian security officials said. A fifth Palestinian later died of his wounds.
An Israeli military spokeswoman confirmed the airstrikes on the cars carrying members of Hamas' armed wing, the al-Qassam Brigades, adding a senior commander she identified as Mohammed Abu Hard who was involved in rocket attacks at Israel was among them.
Palestinian militants earlier attacked an Israeli border police checkpoint and a Jewish settlement in and near Jerusalem late Thursday.
A border policeman was killed and a policewoman was moderately injured when gunmen opened fire from short range at the checkpoint in East Jerusalem's Shu'afat refugee camp.
And two Palestinian attackers were killed after infiltrating a religious school in the Kfar Etzion settlement, south of Jerusalem. They were overpowered and shot after stabbing and injuring two local security guards.
Friday's airstrikes come after two days of chaos in Gaza, in which Hamas militants blew up a wall on the Strip's southern border, allowing hundreds of thousands of Gazans to cross back and forth freely into Egypt to buy scarce supplies.
Israel declared a high alert along its own southern border, amid fears militants from Gaza might attempt to infiltrate the country from Egypt, whose long border with Israel is less heavily secured than Gaza's.
A militant offshoot of Palestinian President Mahmoud Abbas' Fatah movement claimed responsibility for the shooting attack in Shu'afat.
Abbas and Israeli Prime Minister Ehud Olmert agreed to meet Sunday to debate the crisis in Gaza, Israel Radio reported.
Abbas demands Israel ease its tight blockade of the Strip, which had triggered the storming of the Gaza-Egypt border early Wednesday.
Israel, however, has said it will not do so unless daily rocket attacks at its southern towns and villages end. Militants fired nine such rockets and mortar shells from Gaza Thursday, the army said.
Responding to a surge in the rocket attacks, Israel Friday last week completely sealed its border crossings with Gaza. It then opened two of its border crossings Tuesday, allowing in humanitarian aid and diesel for Gaza's only local power plant and for hospital generators.
But it announced a new policy, under which the entry of humanitarian aid and fuel would be down to the bare minimum necessary to avoid a humanitarian crisis.
The goal, Israel said, it to step up the pressure on the militants who are firing the rockets. But human rights groups have condemned the move as collective punishment.
Egypt's decision to re-close the border after the two-day Palestinian shopping spree in its towns near Gaza followed pressure from the United States and Israel, which is concerned that weapons, militants and cash for radical factions crossed over freely along with the scarce goods Gazans have been stocking up on.
The Israeli government also issued a travel warning to Israelis in the Sinai, saying Palestinian militants may use the open border to abduct Israeli civilians or off-duty soldiers on holiday in the Egyptian peninsula and take them to Gaza.
Friday, meanwhile, was the second anniversary since Hamas unexpected victory over Abbas' secular Fatah in parliamentary elections, which has since led to a relentless power-struggle that culminated in the radical Islamic movement's Gaza take-over in June.