ALEXANDRIA - Christians clashed with Egyptian police in the northern city of Alexandria on Saturday, furious over an apparent suicide bombing against worshippers leaving a New Year's Mass at a church that killed at least 21 people. It was the worst violence against the country's Christian minority in a decade. The Interior Ministry blamed "foreign elements," and the Alexandria governor accused al-Qaeda, pointing to the terror network's branch in Iraq, which has carried out a string of attacks on Christians there and has threatened Egypt's Coptic Orthodox Christian community as well. As the rioters threw stones and bottles, police fired rubber bullets and tear gas to disperse them. Some of the protesters beat Muslim passers-by. Nearly 1,000 Christians were attending the midnight Mass at the Saints Church in the Mediterranean port of Alexandria, said Father Mena Adel, a priest at the church. The service had just ended, and some worshippers were leaving the building when the bomb went off about a half hour after midnight, he said.