ALEXANDRIA - The Egyptian government has accused "foreign elements" of carrying out the fatal bomb attack on a church in the northern city of Alexandria that killed 22 people and injured 79 on Saturday. The Interior Ministry said the attack on the Coptic Christian Church of the Saints 20 minutes after midnight was a suicide bombing in which the bomber probably died. Four policemen who had been guarding the church were among the injured in the blast during a New Year's Eve service. "Foreign elements were behind the planning and implementation of the attack," the ministry said in a statement. Investigation showed that the bomber had used a 'locally-made' bomb containing nails. The attack sparked an angry response from Christians who stoned a nearby mosque, leading to clashes with the police. The Grand Sheikh of the country's highest Islamic authority condemned the attack, saying it could not have been carried out by Egyptians. "It is a foreign crime implemented on Egyptian land," Ahmed al-Tayyeb told state television. Authorities tightened security around churches across the country in the wake of the attack. Copts meanwhile held demonstrations outside the church in Alexandria.