|Egypt is on high alert following Saturday's bombing at a Coptic church in the northern city of Alexandria [AFP]
Egyptian police are investigating whether the people behind a New Year's Day church bombing in the country's north have links to Al-Qaeda in Iraq.
Egypt was on high alert on Monday following the attack at a Coptic church in Alexandria, as officials revised the death toll from the bombing to 19.
Government officials said early findings suggest "foreign elements" were behind Saturday's bombing and that the attack seemed to be the work of a suicide bomber.
"The security forces have confirmed that finger of suspicion indicates that the culprit was a suicide bomber linked to al-Qaeda," a security source, who asked not to be identified, said.
Investigators are now scrutinising the details of people who have travelled between Iraq and Egypt in the past month.
List of suspects
Al Jazeera's Ayman Mohyeldin, reporting from Cairo, said Egyptian police are still trying to determine what are believed to be the remains of the bomber who carried out Saturday's attack.
"So far they have narrowed down the list of suspects they have in custody to about 25 people," he said.
"They have also asked Egypt's ports and airports and other entry points to provide a travel log of all the people who have entered Egypt in the past month or so who may have entered from Iraq.
"They believe given the evidence they have gathered that it may have been some type of cell that was operating in Egypt that was inspired or working closely with groups in Iraq."
The Copts are the biggest Christian community in the Middle East and account for up to 10 per cent of Egypt's 80 million population.
The bombing came as nearly 1,000 faithful left al-Qiddissine church, and it sparked angry clashes between Coptic Christians and police as protesters demanded more protection for Egypt's Christians.
The attack was the worst act of violence against Egypt's Christian minority in a decade.
It came two months after al Qaeda-linked fighters in Iraq attacked a Baghdad church and threatened to strike Coptic churches in Egypt, accusing the Egyptian Christian denomination of mistreating female converts to Islam.
Protection around Copt places of worship was discreetly stepped up after the threats, as Hosni Mubarak, the Egyptian president, said he was committed to protecting the Christians "faced with the forces of terrorism and extremism".
Source: Al Jazeera and agencies