Two of the protesters lay dead after the shooting, though police denied involvement.

Chants of ``too much blood!'' rose from the crowd as protesters called Friday for an end to the U.S.-backed interim government.

``We are living a nightmare under this de facto government. All they do is kill Aristide supporters,'' said Bolivard Yvena, a 24-year-old Bel Air resident with a photo of Aristide taped to her chest.

Haitian police agreed to stay away to avoid more clashes, said Dan Moskaluk, a spokesman for the U.N. Civilian Police force. Moskaluk, who estimated up to 2,500 people marched, said U.N. officials have not determined if police fired on protesters Monday, but he acknowledged there was concern over their use of force.

The 7,400-member U.N. peacekeeping force and the interim government are struggling to contain violence ahead of promised general elections this fall.

Several parts of the country remain under the control of former soldiers and gangsters who led the three-week rebellion that ousted Aristide on Feb. 29, 2004 - raising concerns about their ability to sway elections.

More than 400 people have been killed in Port-au-Prince since Aristide loyalists - including armed gangs - intensified protests four months ago to demand his return.