CAIRO - Egypt said on Sunday an al-Qaida-linked group in Gaza is behind the New Year's suicide bombing that killed 21 Christians and wounded about a hundred outside a church in the Mediterranean port city of Alexandria. The announcement was made Sunday by Interior Minister Habib al-Adly in a ceremony attended by President Hosni Mubarak, senior cabinet ministers and top police officials. He named the group as the Army of Islam. The Alexandria bombing was the deadliest attack against Christians in Egypt in more than a decade. Security officials said an unspecified number of people have been detained in connection with the bombing but gave no more details. They spoke on condition of anonymity because they were not authorized to share the information with the media.