Pope Shenuda 111 holed himself up in Anba Bishoy Monastery

The head of Egypt's Coptic Church has holed himself up in a desert monastery to protest the arrest of Christians demonstrating against a reported attempt to forcibly convert a priest's wife to Islam.

Pope Shenuda III withdrew 10 days ago to the Anba Bishoy monastery, a fourth century retreat in the Wadi Natrun depression west of Cairo, his office told AFP Thursday.

The pope's whereabouts had been unknown since he cancelled two successive weekly meetings at Cairo's Saint Mark's Cathedral.

"He told us last Saturday that he would return when he feels his mind is at peace," the patriarch's office said.

Other church sources said the cleric had vowed not to resume his normal duties until the authorities released all 37 Copts who were detained during December 8 clashes with security forces in the capital.

Worshippers took to the streets outside the cathedral as rumours spread that Wafaa Constantine, wife of a Coptic priest in a town north of Cairo, had been abducted and forced to convert to Islam by her civil service boss with the complicity of police.

A state-owned weekly, Al-Musawar, had charged that the 48-year-old woman wanted to convert but had been prevented by her family.

But the pope's office said Wafaa Constantine had returned to her church on Tuesday and been accepted back into the congregation.

"The patriarch granted her his mercy and assured her that she remained in the church," it said.

Egyptian law gives the Coptic Church authority to vet all conversions to Islam to ensure they were not made under duress.