Egyptian riot police fired tear gas and clashed with demonstrators staging protests nationwide Wednesday against President Hosni Mubarak's "dictatorship," arresting more than 200 people, organizers said. Pro-reform activists have escalated their campaign for constitutional and political reforms in the country in recent weeks, with many calling on Mubarak to step down when his mandate expires later this year. Police clashed with hundreds in the town of Fayyoum, as well as in Mansoura and Zagazig in the Nile Delta region, and fired tear gas to disperse the crowds, the opposition Muslim Brotherhood said. It said security forces arrested about 100 protesters in Fayyoum and another 100 in Zagazig in a day of coordinated rallies up and down the country it organized to press for political reforms. The Brotherhood also reported demonstrations in the Mediterranean city of Alexandria, Tanta, and Damanhour in the Delta region and in the capital, Cairo. Interior Ministry sources said police detained 80 protesters in Mansoura, 100 in Zagazig and 30 in Fayyoum. "No to dictatorship," a group of an estimated 1,000 protesters chanted outside the Fatteh Mosque in central Cairo.