RAFAH, Egypt (Reuters) - An Egyptian border guard and a Palestinian youth were killed during border clashes between Hamas and Egyptian security forces on Sunday in turmoil triggered by Israel’s assault on Gaza.

An Egyptian security source said forces of the Palestinian Hamas group had also shot an Egyptian policeman in the leg.

The incidents took place near the main border crossing between Egypt and Gaza, where Egyptian riot police fired in the air to try to drive back Palestinians who had managed to penetrate the border wall.

The events are likely to aggravate tense relations between Hamas and the Egyptian government, which says that Hamas is largely to blame for the Israeli onslaught. Israeli air strikes have killed nearly 300 people in Gaza in two days.

Witnesses said that during the confusion of the assault, dozens of Palestinians crossed into Egypt from Gaza as Egyptian riot police fired in the air.

Reuters correspondent Yusri Mohamed said he had met several Palestinians on the Egyptian side of the border who told him they had slipped across at holes in the border wall.

It was not immediately clear how the holes appeared in the wall but the exodus began within an hour of Israeli air raids aimed at tunnels along the Egyptian border.

An Egyptian security official said later that the authorities had detained about 40 Palestinians who had entered Egypt without going through the usual formalities.

Bursts of gunfire were audible by telephone from Rafah as Egyptian police tried to frighten the Palestinians off. Gaza hospitals said 10 people were wounded by Egyptian police fire.

Egyptian state television said a border guard officer was killed by fire from Hamas security forces.

In Gaza, a medical worker said that a 21-year-old Palestinian died of his injuries at a hospital in Gaza’s Rafah town after being shot in stone-throwing clashes with Egyptian security forces.

Egypt has been cooperating with Israel for months in the blockade of Gaza, restricting the flow of goods and people across the Rafah crossing, Gaza’s only access point that is not under direct Israeli control.

Egypt reopened the main crossing point on Sunday to let out some of the Palestinians injured in the Israeli attacks.

In January, tens of thousands of Palestinians crossed the border into Egypt after Hamas blasted holes in the wall. It took the Egyptian authorities days to persuade them to leave.