that killed nearly two dozen Christians and wounded 100 others.
The same group also kidnapped BBC journalist Alan Johnston and held him for more than three months three years ago before freeing him.
The direct accusation by Egyptian officials may have direct and deep repercussions on Hamas, which has been warned by Egypt lately to rein in rival terrorists from attacking Israeli civilians and soldiers with missiles and mortars.
"We have decisive proof of their heinous involvement in planning and carrying out such a villainous terrorist act at a Coptic church January 1", said Interior Minister Habib el-Adli. He specifically named the Army of Islam in a televised speech Sunday.
The deadly attack, the worst against Egyptian Christians in more than 10 years, as Coptic protesters clashed with Egyptian police. The Copts, approximately 10 percent of the primarily Muslim Egyptian population, have charged the government with systematic prejudice against them.
Egyptian officials said that authorities have arrested several terrorists suspected of being involved in the attack at the church during midnight mass.