CAIRO - Egyptian security forces began throwing up a cordon of steel on Thursday as Coptic Christians prepared to mark Christmas after a New Year's Day church bombing killed 21 people in Alexandria.
As police released a sketch of the suspected bomber, security officials said at least 70,000 officers and conscripts would fan out across the country to secure churches as Copts attend Christmas Eve mass.
Drivers would be banned from parking their cars in front of churches, which would be tightly monitored by explosive detection teams and police officers, the official said.
Armoured cars would also be stationed next to churches.
Some Muslims, he said, would also show up at churches to act as human shields in a show of solidarity with Egypt's beleaguered Christian community, which accounts for 10 percent of the country's 80-million people.
Meanwhile, police released a sketch of the suspected suicide bomber's face, reconstructed from the remains of a severed head found on the roof of the Alexandria church.
The image was published on the front pages of government newspapers.
No-one has yet claimed responsibility for the attack, which came after a Qaeda-linked group in Iraq threatened Egypt's Copts after saying it carried out a deadly October assault on a Syriac Catholic church in Baghdad.
The group, the Islamic State of Iraq, said it would attack Copts if their church failed to release two women the group claimed being held against their will after converting to Islam.
Several weeks before the attack, a website linked to Al-Qaeda published a list of Coptic churches it said should be attacked in Europe and Egypt, including the one targetted on January 1.
It urged "every Muslim who cares about the honour of his sisters to bomb these churches during Christmas celebrations, when they will be most crowded."
The bombing sparked days of protests and riots around the country that injured dozens of policemen and protesters.
Egypt, the most populous Arab country, witnessed a resurgence in attacks by Islamist militants in the past decade after the government battled an onslaught in the 1990s that included an attempt abroad to kill the president.
President Hosni Mubarak has vowed to find those responsible for the New Year's Day bombing which he said targeted all Egyptians, regardless of their faith, and blamed "foreign hands."
"It is a terrorist operation that is alien to us," Mubarak said, pledging his government would track down the culprits and urging Muslims and Christians to close ranks.
"All of Egypt is targeted. This blind terrorism does not differentiate between Copts and Muslims," the president said on Saturday.
Last year began with a massacre of six Copts and a Muslim security guard after a Coptic Christmas Eve mass and ended on a tense note after two Coptic protesters died in clashes in a protest over a Cairo church permit.