Reports say Egyptian police have arrested a founding member of the country's most prominent Islamic militant group.

Salah Hashem, who helped found al-Gamaa al-Islamiya (the Islamic Group) in the late 1970s, was arrested in his hometown of Sohag and taken to Cairo for questioning, according to the reports.

We don't have information about the reasons behind his arrest, which was a surprise for us

Salah Hashem's lawyer

Correspondents say the arrest comes as a surprise because Mr Hashem played a key role in influencing many militants to renounce violence.

Al-Gamaa al-Islamiya was blamed for the 1997 massacre of 58 foreign tourists in the southern city of Luxor.

"We don't have information about the reasons behind his arrest, which was a surprise for us," a lawyer defending Islamic militants told al-Jazeera satellite TV station.

Mr Hashem's wife, Nabila Abdel-Hay, is reported to have said her husband, who works as an engineer in the electricity authority in Sohag, disappeared on Saturday after he left for work.

She reportedly said that when she asked the authorities about his whereabouts, she received no answer. Their phone was later cut off.

Reformed militant

Mr Hashem was tried in absentia for his role in the assassination of President Anwar Sadat in 1981 and was acquitted.

Between 1982 and 1985, he worked in Saudi Arabia.

He announced in the late 1980s that he had left the Gamaa al-Islamiya and called on the militants to renounce violence and promote peaceful politics.

Since returning to Egypt, he was arrested several times.