The Egyptian state prosecutor on Wednesday ordered 147 detained members of the Muslim Brotherhood to be investigated following demonstrations in several cities across Egypt's north, a judicial official said. The detainees are being accused of holding unauthorized demonstrations and rioting, added the official on condition of anonymity because he was not authorized to speak to the media. Thousands of members of the opposition Muslim Brotherhood demonstrated across the Nile Delta Tuesday, accusing the government of preventing them from participating in upcoming municipal elections next week. The demonstrators hurled stones at police, who responded by firing tear gas. Authorities have launched a crackdown on the group over the past year putting more than 800 of its members and potential candidates behind bars. The Brotherhood has been banned in Egypt since 1954 but its members have won parliament seats by running as independents in elections. The group surprised everyone by taking 88 seats in the 454-member parliament in 2005 elections. Since registration for local balloting started March 4, few of the 10,000 Brotherhood hopefuls have managed to officially register as candidates.