The daily al-Masry al-Youm newspaper, said the detained salafists were accused of forming a group to support the Brotherhood, especially in elections due later this year for the Shura Council, the upper house of Egypt's parliament.

It said the detentions of the salafists had started this month after the Muslim Eid al-Adha holiday and accelerated alongside a crackdown against Brotherhood members, scores of whom have been detained.

Egyptian authorities launch regular crackdowns on the Muslim Brotherhood, which operates openly despite being officially banned in 1954.

But some analysts say the government is preparing a wider assault on the group after Hosni Mubarak, the Egyptian president, said this month the Brotherhood posed a threat to Egypt's security.

University protests

The government was also angered by a protest march at al-Azhar University last month in which Islamist students wore militia-style uniforms and black balaclavas.

Egyptian state media said the march showed that the group was forming a militia. This accusation was dismissed by the Brotherhood.

Mubarak has proposed constitutional amendments that include a ban on forming political parties based on religion. The Brotherhood says it wants to establish a civil, democratic party that is not exclusive to Muslims.

Brotherhood members elected as independents hold 88 seats in the 454-member lower house of parliament, which is dominated by Mubarak's ruling National Democratic Party.

Torture allegations