CAIRO - Egypt has tightened security around churches ahead of the Christmas, which Coptic Christians celebrate Friday. Pope Shenouda III, the head of the Coptic Orthodox Church, will lead the Christmas Mass with Muslims participating in solidarity with Copts after a deadly attack against a church in the coastal city of Alexandria. "Leave for all officers and soldiers has been cancelled in all governorates as surveillance is heightened near churches and extra preventive measures are in place," a security official said. He added that new checkpoints were set up near churches with extra police personnel deployed. "All these measures are preventive in case something unusual takes place," he said. The official pointed out that the ambulance and firefighting personnel were also ordered to be on high alert. "The tightened security measures will be in place until further notice," he said. The bombing outside the Al-Qiddissein (The Two Saints) Church on the New Year's Eve killed 23 Copts and touched off riots and protests by Christians, who feel they are targeted and discriminated against and do not get adequate protection from authorities. No group has claimed responsibility for the attack on Coptic Christians leaving a midnight mass about a half hour into the New Year, the worst attack on Egyptian Christians in a decade. In the immediate aftermath, President Hosni Mubarak blamed foreigners while the Alexandria Governor accused al-Qaeda, pointing to threats against Christians by the terror network's branch in Iraq. Alexandria, a famed city of antiquity which a century ago was home to a mix of Muslims, Christians, Jews and foreigners, has become a stronghold for Islamic hardliners in the past decade. Stabbings at three Alexandria churches in 2006 sparked three days of Muslim-Christian riots that left at least four dead. Bombing could have been worse "The blast was not because of a car bomb. It was a makeshift bomb carried by a suicide bomber who tried to get into the church to cause more deaths," Magdi Radi, a spokesman for the Government, quoted Minister of the Interior Habib el-Adly as telling a Cabinet meeting Wednesday. He added that the blast was followed by some clashes between Copts and Muslims, which were dispersed by police. Radi quoted el-Adly as urging media outlets not to jump to conclusions as investigations are still underway. "The Interior Ministry will announce all the information it has on time. However, media should consider the current investigation," he said. "Egyptian media should never be dragged into playing a negative role like that played by some foreign media said." The official said that there were 18 identified bodies as four other sacks of human remains are still unidentified. "The final death toll according to the Health Ministry is 18 deaths," Radi said. Meanwhile, Prosecutor General Abdel Meguid Mahmoud and his top aides reviewed investigations in Alexandria Wednesday as they checked all the records of questioning and forensic report. Investigators on Tuesday said they had found a head that may have belonged to the suicide bomber, and which could help identify the attacker. Egyptian authorities suspect the attack was carried out by a suicide bomber with links to al-Qaeda. The Islamic State of Iraq, al-Qaeda's affiliate in Iraq, had threatened in November to attack Egypt's Christians to force the release of two Coptic priests' wives whom they claimed had converted to Islam and were being held against their will. Low-key celebrationsPope Shenouda will head the Coptic Mass tonight in the St Mark Cathedral in Abbasiya in Cairo as Cabinet ministers and Muslims are expected to attend the memorial prayer. "The church will hold the Mass tonight and Pope Shenouda will lead us. We can never reject the hands of solidarity extended by our Muslim brethren," said Bishop Ermia, a secretary of the Pope. Grand Sheikh of Al-Azhar Ahmed el-Tayyeb led a march in Al-Azhar University yesterday to condemn the Alexandria bombing. "Egypt has never and will never have sedition between Muslims and Copts," el-Tayyeb said.