Police arrested the outlawed Muslim Brotherhood's chief strategist along with at least 140 others Thursday after a protest by uniformed students raised fears the Islamist political group is creating a military wing.

Mohammed Khayrat el-Shater, the group's main financier and third highest ranking member, was taken from his home, security officials said, speaking on condition of anonymity because they were not allowed to speak to the media.

They said 140 others were arrested on suspicion of belonging to the Brotherhood, participation in a plot to infiltrate student and worker organizations, and engaging in "unprecedented actions" — including participation in a militia-style demonstration a few days ago at Al-Azhar University outside Cairo.

In that protest, demonstrators wore masks resembling those of the military wing of the Palestinian Hamas organization.

Abdel Gelil el-Sharnoubi, editor of the Brotherhood's Web site, said hundreds of security forces stormed part of a university dormitory where the Brotherhood students were living and arrested everyone there.

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"This round of arrests is a government reaction to a year of strong performance by the group in parliament, in advocating for reforms and in their opposition to the succession of power," el-Sharnoubi told The Associated Press.

The Brotherhood said that, in addition to el-Shater, police arrested more than 180 students and 13 others, including el-Shater's son-in-law.

El-Shater, 55, the Brotherhood's second deputy, joined the Brotherhood in 1974 and has been imprisoned four times for a total of seven years on charges relating to his membership.

Police and security officials could not immediately comment on el-Sharnoubi's allegations.

Following the arrests, hundreds of Al-Azhar students, mostly sympathizers with the Brotherhood, held an angry demonstration inside the campus and called for the release of their colleagues.

The uproar began on Sunday when about 50 student Brotherhood members at the university appeared in black militia-style uniforms during a demonstration on campus.

Police opened an investigation into whether the group was setting up a military wing, something the Brotherhood denies. The group has stressed that the students acted on their own without coordination with top leaders.

The students issued a statement apologizing for the parade, saying it was "misinterpreted."

"We just wanted to attract attention to our issues, but we made a mistake in our move," according to the statement posted on the group's Web site.

The arrests also came five days after release of two key Brotherhood figures, Essam el-Erian and Mohammed Morsi. They were arrested six months ago in a wave of pro-reform demonstrations.

The Brotherhood is outlawed in Egypt and hundreds of its members have been arrested in the past year.

But the banned organization is also Egypt's largest political opposition group. The Brotherhood won 88 of parliament's 454 seats in elections a year ago, with its candidates running as independents.

The group, founded in 1928, established a military wing during the 1948 Middle East war to fight against Jewish forces setting up the state of Israel.

The militia also fought the British army, which stayed in Egypt until its withdrawal in 1956, and was accused of attempting to assassinate former President Gamal Abdel-Nasser.

Egypt officially banned it in 1954 and has accused it of aiming to set up an Islamic government.

The Brotherhood renounced violence in the 1970s and in recent months has been increasing its influence in powerful trade unions and challenging President Hosni Mubarak's administration in parliament.

Tarek Hassan, a member of the ruling National Democratic party's policies committee, wrote in the pro-government Rose el-Youssef newspaper that the Brotherhood threatened Egypt's security.

"We want to live in a state without being threatened by terrorist bands, and we don't want to see entities challenging the supremacy of the state," Hassan wrote.

The policies committee is led by Mubarak's son, Gamal, whom some say is being groomed to succeed his father.