Egyptian police opened fire Saturday on a group of 10 African immigrants trying to illegally cross into Israel and arrested four of them, a Sinai security official said. The other six managed to cross into Israel, said the official who spoke on condition of anonymity because he was not authorized to speak to the media. It was not know if any of the six had been injured by the gunfire. The four who were arrested were all Eritrean and told authorities that the six who crossed included three people from Eritrea, one from Sudan and another from the Ivory Coast.