Christian and Muslim clashes in Egypt have left 12 people dead, 238 injured and two Coptic churches in Cairo burned, the state media reported.

Faith and political leaders condemned the weekend violence, which was triggered by rumors that a woman who had converted to Islam was being detained at the sixth-century Coptic Church of St. Mena in the working-class neighborhood of Imbaba in northwest Cairo.

It’s the worst sectarian violence since protests in February overthrew Hosni Mubarak, Egypt’s long serving president, and the clashes are presenting fresh challenges to the military-led government.

Members of the Coptic community there were reportedly forming groups for self-defense saying they expect more clashes in the coming months. The groups will protect churches as well as homes and businesses owned by Copts.

“Now we are really afraid,” said the Rev. Arshileadis Mar Mina, a priest at the Mar Mina church, adding, “they are people who are systematically attacking us and there are no police or military to protect us.” He was quoted by the Al Masry Al Youm independent newspaper.

The trouble reportedly started on May 7, when nearly 500 Muslims who are followers of the Salafi fundamentalist Islamist ideology attacked the church demanding the release of Camelia Shehata, the wife of the priest there, alleging she was being held hostage after conversion.

The mobs then lobbed firebombs at homes, shops and the church, setting its facade on fire. Later, a separate group set on fire the nearby Virgin Mary church. “A Catholic church was also attacked, along with some Coptic Orthodoxes,” said the Rev. Luciano Verdoscia, a missionary who has been working in Cairo for several years.

On April 29 Muslims held a sit-in outside San Marco Cathedral to demand Shehata’s release. This prompted several Coptic movements to call for a protest march on May 6 to protect the cathedral in the Cairo suburb of Abbasseya.

Islamic clerics have denounced the violence, and the government has arrested 190 people, warning that anyone who threatens the military-ruled country’s security will face “an iron fist.”

The Christians have, however, alleged the military was not doing enough to protect them. “These events do not benefit either Muslims or Copts,” said Ahmed al-Tayyeb, the Sheik of al-Azhar.

Muslim are in the majority in Egypt with Christians accounting for 10 per cent of the 80 million population.