Port-Au-Prince, Haiti (CNN) -- Candidates wound up a flurry of election campaigning before a midnight deadline Friday night amid reports of a violent attack on one of the candidates' campaigns.
The campaign of flamboyant komba-singer-turned-presidential-candidate Michel "Sweet Micky" Martelly issued a statement late Friday night, claiming he had survived an "assassination attempt" in the town of Les Cayes in southern Haiti.
"Many wounded, at least one dead," the campaign said in a press release.
Haitian police officials have not responded to phone calls from CNN. A spokesman for the United Nations confirmed to CNN there had been a clash in Les Cayes late Friday night, though he could not say whether there were casualties involved.
"It's a confrontation between Martelly partisans and the (supporters) of another Inité senator," Jean-Francois Vezina, a spokesman for the United Nations police detachment in Haiti, told CNN Saturday.
Inite (Unity) is a well-funded political party endorsed by outgoing President Rene Preval. Its presidential candidate, Jude Celestin, leads the largest block of candidates for seats in both houses of parliament, which are also up for grabs in Sunday's election.
"The security guard of the Inite party used a weapon," Vezina said. "The only thing that we've done there is to send a Senegalese Force Police Unit to take control of the election there."
Tensions have mounted in Haiti ahead of Sunday's national elections, scheduled to be held within a year that saw a massive earthquake, a spreading cholera epidemic and recurring signs of government instability.
Eighteen candidates are running for the post of president. Seats are also up for grabs in the Senate and in the lower house of parliament.
Nearly all of the candidates have campaigned on similar platforms -- fighting corruption, creating jobs, and addressing a series of natural disasters that has left the Caribbean nation reeling and prompted many to urge for a postponement of Sunday's vote.
Haitian elections have been historically troubled by violence as well as allegations of fraud and intimidation and the run-up to Sunday's vote has not been peaceful.
Last Monday, clashes erupted between supporters of two rival candidates in another southern town, resulting in at least two deaths.
"Tempers are flaring, there is some political discontent," said Bernice Roberts, senior Haiti analyst with the International Crisis Group. "There is a perpetual crisis of confidence among political actors. Plus there's a high level of social frustration regarding the response to the earthquake, regarding the response to cholera."
According to Haiti's Ministry of Public Health, more than 1,600 people have died as a result of the cholera epidemic that was first discovered on the island last month. More than 60,000 people have been treated for the deadly bacteria.
Religious leaders, meanwhile, have been calling for calm ahead of the vote.
"We are praying for peace on election day," said Max Beauvoir, Haiti's "Supreme Servitor," or highest ranking voodoo priest, in an interview with CNN on Friday.
Haitian authorities are imposing strict measures to ensure security on election day.
After midnight Saturday, only drivers with special passes from the Conseil Electoral Provisoir, Haiti's main electoral body, will be able to operate cars or motorcycles anywhere on Haiti's roadways, according to CEP spokesman Richardson Dumel.
Businesses are also banned from selling alcohol from 8 p.m. Saturday until Monday, he said. Gun licenses are also temporarily suspended from Saturday night until Monday.