Egypt's Interior Ministry says a blast at a church in Alexandria was caused by a suicide bomber who tried to storm the entrance before being stopped by police.
The ministry said three policemen were among those killed in Sunday's attack, without providing an overall toll. The Health Ministry said 11 people were killed and another 35 were wounded.
It was the second of two attacks on Coptic churches that were packed with worshippers celebrating Palm Sunday. The first, in the Nile Delta town of Tanta, killed 26 people and wounded around 70.
The Islamic State group claimed both attacks.