Police arrested 73 members of the Muslim Brotherhood on Thursday, in what appeared to be a pre-emptive strike against the country's largest Islamic group ahead of elections and a key parliamentary debate, spokesman for the police and the Brotherhood said. A Brotherhood executive said the detentions risked provoking violence, not from the group itself but from those who would conclude that the state was leaving no scope for peaceful Islamic political activity. The arrests bring the total of Brotherhood members in custody to just under 300, according to figures provided by the group and Human Rights Watch. Police did not give a reason for Thursday's early morning detentions, but those arrested were mostly Brothers who were expected to stand in the April elections for the Shura Council, the upper house of parliament, as well as assistants to the group's legislators, said Abdel Gelil el-Sharnoubi, the editor of the Brotherhood's Web site. El-Sharnoubi said the group had not yet chosen its candidates for the Shura polls, "but the government targeted figures who are popular in their provinces and are expected to run the elections." The Brotherhood did suprisingly well in the 2005 legislative elections, winning 88 seats in the 454-member parliament. The government postponed the 2006 municipal elections for two years, apparently out of fear of big gains by the Brotherhood. Brotherhood candidates stand as independents in elections as the group has been banned since 1954. But their campaigns are financed by the Brotherhood and voters know their allegiance. "They also arrested a number of legislators' assistants in order to paralyze the lawmakers," el-Sharnoubi added. President Hosni Mubarak has asked the legislature to amend 34 articles in the constitution as part of a political reform package. The opposition, of which the Brotherhood is by far the largest component, has criticized the amendments as doing little to advance democracy. One amendment would ban the formation of political parties with a religious foundation - a restriction clearly aimed at the Brotherhood. Abdel Moneim Aboul Fotouh, a Brotherhood executive, acknowledged that the crackdown would impede the group's ability to campaign. "There is no doubt about that. Those who have been arrested are national, reputable people," he said on Al-Arabiyah satellite TV. But the mass detention was irresponsible, he added. "This is an indirect call by the regime for violent forces to become active because it is crushing all the peaceful factions, and at the head of them is the Brotherhood," he warned. The authorities have intensified their campaign against the Brotherhood since December when student members staged a militia-style demonstration at Al-Azhar University in Cairo. The parade, which Brotherhood leaders said was unauthorized, provoked fears that the group was forming a military wing. Last week Mubarak signed an order to put 40 Brothers on trial in a military court on charges of money laundering and terrorism. The accused include the group's No. 3 leader, Khayrat el-Shater, executive Mohammed Ali Bishr, and a millionaire and patron of the group, Hassan Malik. The Human Rights Watch said in a statement Thursday - before the day's arrests became known - that the police had detained a total of 226 group members "solely for exercising their rights to freedom of expression and association" since December. Sarah Leah Whitson, the Middle East director of Human Rights Watch, accused the government of trying to crush Egypt's largest opposition movement. "The government has shown once again that it cannot tolerate any criticism," she said.