Demonstrators, who have been taking to the streets for repeated clashes with Mr Aristide's supporters over the past few months, accuse the president of being corrupt and anti-democratic, claiming he fixed the results of parliamentary elections four years ago.
The most recent crisis began after hundreds of students and other government opponents swelled the ranks of a protest march through the capital which was met by government supporters, armed with clubs, bottles and pistols. "We have no future," said a student, Rodney Williams. "We are not afraid."
Police fired in an attempt to disperse the crowds as pro-Aristide groups tried to block the demonstration, which turned into bloody chaos.
Students were beaten with bars and hit with stones as armed men raided markets to steal cash from tills and guns from security guards. A pedestrian was shot and killed and witnesses say one of the gunmen, bearing pro-government stickers, was shot dead by a police officer.
The clashes have marred the bicentennial celebrations of the nation's independence from French rule, becoming the world's first black-led republic. Haiti has since been plagued by political violence and foreign intervention, with 21 of its leaders overthrown and only eight having survived a full term in office.
Haitians have a life expecancy of 53, with the highest rate of HIV/Aids infection outside Africa and an estimated 80% of its population living below the poverty line.
Mr Aristide became the country's first democratically elected leader but was deposed in a coup in 1991 only to be restored to power by an American-led invasion in 1994.
In 2000 he was elected to a second term in a landslide but has since been in almost permanent conflict with the opposition, which accuses him of crushing dissent and mismanaging the economy.
Mr Aristide has promised to hold legislative elections this year but insists that he will serve out his term until 2006.
Opposition to Mr Aristide's government spans political parties, some members of the clergy and businesses, but in a country where 40% of the population are under 18, students have a particular potency.
Last month at least two dozen students were injured in violence that broke out after police separated Aristide supporters. The rector of the University of Haiti, Pierre-Marie Paquiot, was beaten with an iron bar and at least four students were shot.
Haiti has drifted towards international isolation over the past four years, despite the presence of the South African president, Thabo Mbeki, at the bicentennial celebrations.
Many foreign donors have cut off support since Mr Aristide's return to power in 2000. The Organisation of American States, which sent observers to the parliamentary elections, refused to oversee the subsequent presidential race.
The UN secretary general, Kofi Annan, accused Mr Aristide's dominant political party, Fanmi Lavalas, of violating democracy by refusing to recount the results from the disputed May 2000 parliamentary elections. The UN mission to Haiti was later withdrawn.
Haiti's once promising tourist industry collapsed long ago. The impoverished island has increasingly found itself used as a staging post for Colombian drug-smugglers heading for the United States.