Christian-Muslim confrontations have increased in Muslim-majority Egypt since the overthrow of former President Hosni Mubarak in 2011 gave freer rein to hardline Islamists repressed under his rule.

Four Christians and one Muslim were killed when members of both communities started shooting at each other in Khusus outside the Egyptian capital, the sources said.

State news agency MENA put the death toll at four.

The violence broke out late yesterday when a group of Christian children were drawing on a wall of a Muslim religious institute, the security sources said. No more details were immediately available.

MENA quoted a Christian official as saying unidentified assailants had attacked a local church during the clashes and set parts of it on fire. Police had stepped up security at the church after Muslim youths began gathering in the area.

The town was quiet on Saturday with a heavy security presence, a security source said. Some 15 police cars were patrolling the streets. Police detained 15 people.

President Mohamed Mursi, a Muslim Brotherhood leader elected in June, has promised to protect the rights of Coptic Christians, who make up about 10 percent of Egypt's 83 million people.

"The sectarian riots which happened in Khusus are unacceptable and grave," Saad al-Katatni, the head of the Brotherhood's political party, said on his Facebook website. "There are some who want to set Egypt ablaze and create crises."

Sectarian tensions have often flared into violence, particularly in rural areas where rivalries between clans or families sometimes add to friction. Love affairs between Muslims and Christians have also sparked clashed in the past.

Since Mubarak was ousted by a popular uprising, Christians have complained of several attacks on churches by radical Islamists, incidents that have sharpened longstanding Christian complaints about being sidelined in the workplace and in law.

As an example, they point to rules that make it harder to obtain official permission to build a church than a mosque.

Last month, a court sentenced a Muslim to death for killing two people in a dispute with Christians in a southern town.