The Egyptian Interior Ministry said that a suicide bomber with foreign links was probably responsible for the church attack in Alexandria that killed 21 people.
"It is probable that the bomb that exploded was carried by a suicide bomber who died among the crowd," the ministry said in a statement, adding the bomb was packed with pieces of metal to cause the maximum amount of harm.
The ministry statement said that given the methods that currently prevail in terrorist activities at the global and regional level, "clearly indicate" that the bombing was "planned and carried out by foreign elements."
A health ministry official in Alexandria said 21 people were killed and 79 wounded. The blast jolted the country's Christian community, the largest in the Middle East.
Nearly 1,000 Coptic Christians were present at the Saints Church in the Mediterranean port city of Alexandria for the mass at the time of blast, Father Mena Adel, a priest at the church, was quoted as saying by the local media. The service had just ended and worshippers were leaving the building when the explosion took place in front of the church, about half-an-hour after midnight.
No one has so far claimed responsibility for the attack on the Coptic church, which belongs to the Oriental Orthodox family of churches, but a group calling itself 'Al Qaeda in Iraq' has vowed to attack churches in Egypt. The group threatened to attack Egyptian Copts if their church did not free two Christian women, who it alleged had been "imprisoned in their monasteries" for having converted to Islam. It earlier kidnapped Christian worshippers in the church of Lady of Salvation in the Iraqi capital of Baghdad.
After the blast, Egyptian President Hosni Mubarak urged the nation's Christians and Muslims to unite against "terrorism", but tempers continued to flare hours later as the Christian protesters clashed with Muslims. The minority community also clashed with police.
Witnesses said Christians hurled stones at police and a nearby mosque, chanting: "With our blood and soul, we redeem the cross". Earlier, the interior ministry had said two cars parked in front of the church were the source of the blasts.
An interior ministry official noted that the bomb was locally manufactured but expert on Islamist groups Diaa Rashwan insisted that the techniques used in manufacturing the bomb were not local. Another expert on security affairs Rifat Sayid Ahmed said it was a direct message from al-Qaeda by which it wanted to instigate sectarian struggle within Egypt and depict it as a country where both sects cannot live together.The Copts are the largest Christian community in the Middle East, who account for up to 10 per cent of Egypt's 80 million population.