CAIRO (AFP) - Egyptian security forces were on the alert on Saturday on the eve of a general election, after activists clashed with police at the end of a campaign marred by violence and a crackdown on the opposition. Thousands of activists demonstrated in support of their candidates throughout the Nile Delta and in the south of the country on Friday night as campaigning for the vote officially concluded, security officials said. Several of the rallies turned violent after supporters of rival candidates hurled stones at each other, they said. An Egyptian court sentenced 12 people to two years in prison for election campaigning for the banned Muslim Brotherhood, a judicial official said on Saturday, a day before a parliamentary poll. The Alexandria criminal court reached its verdict in a hearing on Friday, the official said. Activists for the banned Muslim Brotherhood opposition group clashed with police in the southern Bani Suef governorate, and at least 15 protesters were arrested. The Brotherhood is expected to win far fewer than the fifth of parliamentary seats it captured in the last election in 2005, after at least 1,200 of its supporters were arrested in the weeks before Sundays vote. There are fears that the election may be marred by violence. More than a dozen people were killed in the last election as machete- and sword-wielding thugs hired by candidates attacked rivals supporters and police clashed with protesters. This election will take place amid tear gas, rubber bullets and truncheons, said Brotherhood politburo member and campaign organiser Mohammed Mursi. Most of the detained Brotherhood supporters were later released, but the group says more of its supporters were rounded up each day as they put up posters and handed out fliers. Eleven campaign volunteers in Alexandria have been sentenced to two years in prison after being convicted of distributing fliers bearing religious slogans for the group and supporting their candidates, a judicial source said. The sentences had no precedent in the country, where the use of religious slogans is banned in campaigns. Another 320 Brotherhood supporters are facing similar charges, according to the lawyer Abdel Moneim Abdel Maqsud. The Brotherhood is fielding 130 candidates in the race for the 508 elected seats after the election committee disqualified more than a dozen of them. The public prosecutor is investigating complaints by the ruling National Democratic Party (NDP) that more of the Islamists should be disqualified because they are misrepresenting themselves as independents. The group registers its candidates as independents to circumvent a ban on religious parties. Administrative courts have ordered the cancellation of elections in 24 of 254 districts after rulings to reinstate disqualified candidates, many of them Brotherhood members and other independents, were ignored. NDP secretary general Safwat al-Sharif said on Saturday that the vote would go ahead as scheduled in all districts. Rights groups, who say the election has already been compromised by the arrests of opposition members and campaign restrictions on their candidates, have called on authorities to safeguard voters rights. Turnout is expected to be low as usual in Egypt, where elections are often marred by violence and ballot fraud, according to rights groups. The government insists the election will be fair and the electoral committee says it granted more than 6,000 permits to local civil society groups to monitor the vote and the count. The NDP, which has dominated parliament for more than three decades, is expected to gain seats in parliament at the expense of the Brotherhood. It has about 800 candidates standing in the election.