The head of the Coptic Church in Egypt has appealed for calm as protesters clashed with police for a third day after a blast on New Year's Day killed 23 churchgoers.
Pope Shenouda III also called on government to address Christian concerns about discrimination.
Security has been increased at churches across Egypt, as Copts prepare to celebrate Orthodox Christmas on Friday.
Late on Monday, protesters again clashed with riot police in Cairo, demanding protection and justice.
The official news agency Mena said on Tuesday the death toll from Saturday's church bombing in Alexandria has now risen by two to 23.
On Monday protesters in Cairo's northern Shubra neighbourhood threw rocks at police who tried to block a march by thousands of Copts. Two officers and 12 policemen were wounded, along with at least 10 protesters.
The unrest came a day after 45 policemen were wounded in a clash with Coptic protesters outside St Mark's Cathedral in Cairo.
"I call on our sons for calm, as calm can solve all issues," Pope Shenouda said in a television interview.
"The slogans used by some have transgressed all values and manners... and some have tried to use violence, while violence is absolutely not our method."
In the interview, Pope Shenouda said the state must address Coptic complaints.
"There are laws that are painful to some, and despite our commitment to the laws, the pain is still there, and this needs to be addressed," he said.
The BBC reports the attack in Alexandria was carried out by a suicide bomber who targeted worshippers were leaving al-Qiddissin (The Saints) church after midnight Mass.
It was the worst attack on Christians in Egypt in more than a decade.