CAIRO, 16 March 2007 — Egyptian security forces arrested 18 members of the Muslim Brotherhood yesterday, cranking up pressure on the group ahead of a referendum due in April on constitutional amendments the Islamists deeply oppose. Ten of those detained were rounded up early in the day with eight others being seized later, the security source said.

All were held in the Nile Delta governorate of Sharqiya on charges of “belonging to an illegal organization and for possessing documents describing the ideology of a banned group,” the official said. The Brotherhood, officially banned but tolerated, controls one-fifth of the seats in Parliament through MPs elected on an independent ticket. The official said none of those arrested yesterday was among the leadership.

On Monday, security forces also arrested 18 of the Brotherhood, including one of the Islamist group’s senior members, Mahmoud Ghozlan. The latest arrests are part of a crackdown launched in December after students affiliated with the movement held a militia-style parade on the campus of Al-Azhar University in Cairo.

The government accuses the group of seeking to revive its secret wing from the 1940s that carried out violent attacks. The Brotherhood says the crackdown is aimed at quelling dissent over a series of constitutional amendments proposed by President Hosni Mubarak.

The Brotherhood, which rejects violence, is the strongest opposition force in Egypt. Members running as independents to circumvent a ban on the group won nearly a fifth of the 454-seat lower house of Parliament in 2005. Analysts say the government fears that un

less it stops the Brotherhood now, the group will make more electoral gains that could help it eventually mount a serious challenge to Mubarak’s ruling National Democratic Party.

“It is all because of the constitutional amendments,” a Brotherhood spokesman said about the fresh arrests. “It is to put pressure on the Brotherhood.” Security sources said the arrested men, who included several doctors, teachers and an engineer, were detained in dawn raids in the Nile Delta, where the Brotherhood has strong support.

The constitutional amendments would weaken the role of judges in monitoring elections and an anti-terrorism clause would give police sweeping powers of arrest and broad authority to monitor private communications. The proposed laws would also ban political activity based on religion, quashing Brotherhood hopes of acquiring legal standing as a recognized political party.