The Egyptian Gazette reported TV channels called for calm, while some Muslim and Christian leaders called on followers to put aside their religious differences and focus on what unites them.
"This is more than enough," prominent Islamic preacher Amr Khaled said on TV. "We need to remember that Egypt is in danger."
The British newspaper The Guardian reported Egypt's military rulers held emergency talks with Christian leaders, and Coptic leaders called on followers to fast and pray for three days starting Tuesday.
With the country on edge from violence Sunday that left 24 people dead and scores injured, Ahram Online reported the government Monday executed a man found guilty of killing six Coptic Christians and a Muslim in Naga Hamadi in 2009. Hamam el-Kamony, who attacked the victims outside a church as worshipers left a Christmas mass, had been sentenced to death in January.
While the violence mostly subsided Monday, high tension persisted and the Gazette said fear and grief were palpable on the streets of Cairo.
Field Marshal Mohammed Hussein Tantawi was the target of Coptic protesters' anger despite calling for an investigation into the violence.
"Tantawi you traitor, the blood of Copts is not cheap," shouted one protester outside a Coptic church in Cairo.
Christians threw stones at police outside the hospital where many of the casualties of Sunday's violence were taken and Coptic women dressed in black and carrying wooden crosses mourned the deaths of their "martyrs," The Guardian said.
Caretaker Prime Minister Essam Sharaf called the violence a "setback" and "a conspiracy against the nation," though he didn't name those he thought were behind it.
"Egypt is in danger" the prime minister said. "The past hours were painful for any Egyptian to experience the spilling of civilian and military troops' blood."
He cautioned that sectarian violence and attempts to turn the people against the army were the biggest threat to Egypt.
Potential presidential candidate Amr Moussa said the country was in a "difficult" situation.
"What is happening now reflects the major problems in the relations among all segments of this society," Moussa said.
But the Gazette said some Muslim protesters were reportedly seen in the streets raising the Koran and chanting "Islamia, Islamia" in a call for an Islamic state.
Ahram Online said thousands of Coptic Christians and political activists gathered in a street near the Coptic hospital near downtown Cairo.
The Coptic Christian Church accused Egyptian officials Monday of allowing crimes against Copts to go unpunished, the Los Angeles Times reported.
The church issued a statement saying, "Strangers got in the middle of our sons and committed mistakes to be blamed on our sons," and adding Copts are victims of attacks and discrimination "that occur repeatedly and go unpunished."
Military police Sunday fired on Coptic Christian marchers who protested the burning of a church in Aswan province and accused state TV of inciting anti-Christian agitation. Reports indicate at least 200 people were injured.
Witnesses said the military shot at protesters and ran some over with vehicles.
In Washington, President Barack Obama expressed concern about the violence in Egypt and called for restraint on all sides.
"As the Egyptian people shape their future, the United States continues to believe that the rights of minorities, including Copts, must be respected, and that all people have the universal rights of peaceful protest and religious freedom," Obama said in a statement.
"The next regime will be the same. The policy will never change. The solution to our problems is to prove we are one people, Muslim and Christian, because the regime will stay corrupt," protester Aida Mahrous told al-Masry al-Youm.
Another protester said during clashes Sunday he was taking his wife to a hospital when he was stopped at a military-police checkpoint. He said he was asked about his religion and that his windshield was smashed with a rock when he said he was Christian.
Al-Azhar, Egypt's highest religious institution, called for a new law regulating construction of churches. The flashpoint incident in Aswan that sparked Sunday's protest was an attack on a church attackers said was being built in breach of the law.
Funerals for the victims began Monday. After leaving the church, mourners gathered and began chanting against Hussein Tantawi, Egypt's de-facto ruler, al-Masry al-Youm said.
The Muslim Brotherhood said in a statement:
"There are certain channels, means and times for demanding legitimate demands and all Egyptian people have legitimate demands, not only our Coptic brothers," said the statement. "This is certainly not the right time to demand them since the current government is an interim government and the general conditions are abnormal."
Military prosecutors said they started interrogating 25 suspects implicated in Sunday's violence, state media reported.
Reports that Copts were burning copies of the Koran prompted men to take up weapons and "defend Islam," one witness told Bakyamasr.com.
Protesters also took to the streets in Alexandria, Egypt's second-largest city, witnesses said.