Cairo, Egypt (CNN) -- As mourners gathered at a church to grieve four Christians killed in Saturday clashes with Muslims, fresh violence broke out Sunday, leaving another person dead in Egypt.
The violence erupted at St. Mark Cathedral of Abassiya, a Coptic Christian church in Cairo.
At least 66 people were injured in the clashes, according to Egypt's Health Ministry.
The attackers climbed the walls of the cathedral, and soon the two sides were throwing rocks at each other, state media reported.
At least two Christians were in critical condition at a nearby hospital, the state-run al-Ahram newspaper reported. It was not immediately clear whether the person who died was one of the two.
Police rushed to the scene with armored vehicles and threw tear gas, leading to some cases of asphyxiation, state-run Egynews said.
Five killed Saturday
One Muslim and four Christians were killed in Saturday's clashes in Qalyubia province, officials said.
The violence in the city of Khosous, north of Cairo, broke out after Coptic Christians drew crosses on the walls of a Muslim school, angering members of the Muslim community, said spokesman Ahmed Osman.
Some of those caught in the clashes pulled out weapons and live ammunition.
The alleged perpetrators and other Christians took shelter inside a Coptic church, Osman said. Angry members of the Muslim community tried to storm the building, but security forces arrived in time to prevent them.
Clashes between Muslims and Christians resumed in Khosous on Sunday evening, the state-run MENA news agency reported.
The violence started after unidentified men fired at Christian youths outside the Mar Girguis Church, MENA said, adding that one police officer was injured.
The Health Ministry said eight people were injured Sunday. It was not immediately clear whether the officer was among them.
The Christian minority has been the target of high-profile attacks in the past several years.
The bombing of a major church in Alexandria in January 2011 left at least 21 people dead, and at least 25 Coptic Christians and their supporters were killed in clashes with the army in October of that year. That incident was the bloodiest in Egypt since its revolution in February 2011.
According to the Pew Forum on Religion and Public Life, Egypt's population as of 2010 included an estimated 77 million Muslims and 4 million Coptic Christians.
CNN's Amir Ahmed, Josh Levs and Laura Smith-Spark contributed to this report