More than one-third of Iran's Parliament resigned Sunday to protest a sweeping ban on candidates running in the parliamentary election later this month. The defiant move threatened to plunge Iran's political system into chaos.

One by one, angry lawmakers who have held a three-week sit-in at the huge Parliament building, marched up to the podium and handed their resignations to the speaker. In an emotional statement read aloud during the session of Parliament on Sunday and broadcast live across the nation on Iranian radio, the members who resigned accused powerful conservatives of seeking to impose a religious dictatorship like that of the Taliban, who were overthrown by American-led forces in Afghanistan.

''We cannot continue to be present in a Parliament that is not capable of defending the rights of the people and that is unable to prevent elections in which the people cannot choose their representatives,'' the statement said.

There has been continual tension in Iran between reformers -- the president and much of the Parliament -- who are pressing for greater religious and cultural freedom, and religious conservatives, who control the judiciary and security services.