A bomb attack killed 21 people outside a Coptic church in Alexandria, Egypt late Friday night. Another 24 people were wounded.

The bombing took place as worshipers left a church following a New Year's Eve service. Officials initially suspected that a car bomb was used.

The Interior Ministry later announced that the blast is believed to have been a suicide bombing; however, that version of events was questioned by Christian leaders, who suggested that authorities may wish to blame a suicide bomber in order not to draw attention to the lack of security near the church. Proper security would have prevented a suspicious vehicle from approaching, they said.

While it is not yet clear who carried out the bombing, senior officials in both the Coptic Church and the government pointed fingers at al-Qaeda, which has previously threatened attacks on non-Muslims in Egypt.

Protesters took to the streets after the bombing, with Christians and Muslims clashing near the site of the attack.

Egyptian President Hosni Mubarak urged calm. In a televised address, he said the bombing bore the mark of “foreign hands” seeking to destabilize Egypt.

“This act of terrorism shook the country's conscience... and hurt the hearts of Muslim and Coptic Egyptians,” he said. “The blood of the martyrs in Alexandria mixed, telling us that all Egypt is the target, and that blind terrorism does not differentiate between a Copt and a Muslim.”

The Islamist Muslim Brotherhood condemned the attack as well.

The attack follows months of growing anti-Christian violence in Egypt. Six Christians were murdered in a shooting attack in January, and in November one Christian man was killed by police and 156 were arrested during a protest over construction of a church.

The UK-based Barnabas Fund, a Christian advocacy group, has expressed fears for the safety of Egyptian Christians in the face of incitement. Extremist Muslims have accused Christians of siding with Israel and of holding captive Christian women who have converted to Islam.