Less than two full days since a reported suicide bomber attack against a Christian church in Egypt's second largest city Alexandria left at least 21 people dead and scores wounded, police clashed with protesters across the country as angry Egyptian Christians demand justice. On Sunday, hundreds of Coptic Christians held a sit in at Abbaseya Cathedral in central Cairo, in protest against the attack on New Year's Eve in the northern coastal town. An eyewitness on Sunday told Bikya Masr that the crowds were large and that riot police broke into the cathedral to break up the demonstration. “The police violently beat up protesters inside the cathedral and some are injured badly,” the eye witness told Bikya Masr. “The rest were being held inside, while they were trying to leave. The police is holding the injured inside despite what seems to be some serious injuries and the protesters outside the church are going on a rampage as the police are preventing anyone from getting into the injured and they are trying to break the police cordon,” added the source. They said that police are being “very violent with the protesters.” At least 7 people have been reportedly arrested during the past 48 hours, Reuters reported. Demonstrators at the church in Cairo have been calling for Egypt's Interior Minister Habib al-Adly and Alexandria Governor Adel Labib to be removed from power after the incident. Ironically, the head of the Cairo security forces General Ismail al-Sha'er said “we support the demonstrations that condemns the Alexandria attack,” describing it as a “positive, peaceful protest of Christian and Muslim youth and it doesn't reflect any political agenda.” Elsewhere in Cairo, ministries' buildings such as the Ministry of Foreign Affairs, Ministry of Information and other locations throughout the city. Shortly after midnight on New Year's Eve, as Coptic Christians were leaving a midnight mass service, a bomb exploded, leaving at least 21 dead. The violence was Egypt's first suicide attack in over one year and heightened already tense relations between the Muslim majority and the Coptic minority. Egypt's President Hosni Mubarak addressed the nation early Saturday, denouncing the attack and calling on Egypt's Christians and Muslim to unite in the face of terrorism. “This terrorist act has shaken the conscience of the nation. The blood of our children will not be lost and we will cut off the hand of terrorism,” Mubarak said in his televised address. The president also pointed to foreign involvement in the attack and promised to “cut the hand of terrorism.” The funeral of those killed took place on Saturday in the presence of Alexandria's Governor Adel Labib, who according to Egyptian blogs was attacked by angry locals. At least 1,000 worshipers had attended the Saints Church's New Year's Eve mass. One priest at the church told local press that the death toll could have been much higher if the bomb went off few minutes later as more people were leaving. Most of the injured were Muslims, local reports said. A number of Facebook groups have sprouted up in the past 24 hours to invite Egyptians, religion notwithstanding, to attend the Coptic mass on January 7 to mark the Coptic New Year. Hundreds have already accepted the invitation. “We will go to die with our Christian friends,” one supporter of the campaign said. BM