Egyptian security forces have detained a Shi'ite Muslim activist who campaigned for more rights for Egypt's tiny minority Shi'ite population, security sources and the man's lawyer said on Wednesday.

Mohamed el-Derini, who runs a Shi'ite group called the Supreme Council for the Care of the Prophet's Family, was taken from his home on Monday, and is the second Shi'ite activist arrested in two months in Egypt, lawyer Hossam Bahgat said.

His arrest was the latest in a string of lawsuits and detentions that observers say aim to silence political dissent as Egypt prepares for a transition of power from President Hosni Mubarak, who at 79 years-old has been in power a quarter century.

Security sources said Derini, who was held for 15 months without trial in 2004 to 2005, was being held on charges including contempt of religion and tarnishing the reputation of Egypt's prisons.

Shi'ites are a tiny minority in Sunni-dominated Egypt. Rights groups have complained of police harassment of Shi'ites, apparently motivated by contempt for their beliefs and of suspicion of links with Iran.

"Our experience has been that all the charges that Shia were arrested for or prosecuted under were always political ... The underlying reasons for their arrests have consistently been their religious beliefs," Bahgat, of the Egyptian Initiative for Personal Rights, told Reuters.

He also cited what he described as widespread prejudice against Shi'ites among Egyptian security officers. The Egyptian government says it treats all citizens equally.

Bahgat said the charges against Derini, who had complained of being abused during his previous detention, were linked to an interview Derini gave to the opposition al-Ghad newspaper in which he said torture was widespread in Egyptian jails.

Derini's arrest coincided with an escalating crackdown on critics of all stripes in recent months. Over the past month, Egypt has forcibly closed a human rights group that aided torture victims and sentenced 10 journalists to jail over their work, including four convicted of defaming the president.

Bahgat said Derini's arrest appeared also to be linked to the case of Ahmed Sobh, a fellow Shi'ite who ran the Imam Ali Centre for human rights and who he said was arrested in August on charges of hurting the image of Egypt's prisons and inciting detainees to go on hunger strike.

Bahgat said Derini was being held in administrative detention in a prison near Cairo under emergency laws put in place after the 1981 assassination of President Anwar Sadat.

Derini's wife, Mona Kamal, said her husband had cut back his Shi'ite activism to focus on writing films and television series including a series on the fate of Egyptian prisoners of war held by Israel in the 1967 Middle East war.

Human rights activists say torture is systematic in Egyptian jails and police stations. The interior ministry says those allegations are exaggerated and that it prosecutes police officers against whom it has evidence of torture or abuse.