Prosecution authorities in Upper Egypt's Luxor ordered Friday the detention of Kirollos Shawky for four days pending investigations over allegations that he insulted Islam.

According to the state-owned news agency MENA, Shawky was arrested for allegedly posting pictures insulting Islam on his personal Facebook page. Another six, accused of attempting to use the incident to incite locals to attack Shawky's house with stones, were also arrested.

Safwat Samaan, chairman of Nation Without Borders, a human rights group in Luxor, said on his Facebook page that the 29-year-old Shawky did not post anything insulting to Islam but was rather accused by someone in his neighbourhood of "liking a page titled 'Knights of the Cross' that posted something offensive."

He added that Shawky was not accompanied by a lawyer during the investigation.

Charges of insulting religion go back to the regime of ousted president Hosni Mubarak, widely used then as a pretext to crack down on political activists. However, occurence of the charge significantly rose under the rule of the Supreme Council of the Armed Forces (SCAF) and of rule of Islamist president Mohamed Morsi, who was removed from power last July.

A report issued by the Egyptian Initiative for Personal Rights(EIPR) last September revealed that since the January 25 Revolution until the end of 2012 a total of 63 citizens, both Muslims and Christians, were charged with insulting religion.

Article 98 of Egypt's penal code says anyone convicted of offending religion in any form can face up to six years in prison.