A Brazilian United Nations peacekeeper leads a man out of a polling station after the voting deadline for the municipal elections in Port-au-Prince on Sunday. - Reuters

PORT-AU-PRINCE, Haiti (Reuters):

AN OFF-DUTY police officer was killed and several people were wounded on Sunday during local elections in Haiti, police said.

The officer was shot in the head by gunmen near the slum of Martissant in the capital, Port-au-Prince, police Inspector General Jean Saint-Fleur said.

"We have opened an investigation into the murder of the policeman and other acts of violence while we try to keep the situation under control," said Saint-Fleur.

The motive for the killing was not immediately clear but a witness said the police officer was killed after a dispute with two people linked with a political party.

Haitians were choosing more than 1,000 mayors and other local officials out of more than 29,000 candidates.

The winners of the elections will control the nomination process for an electoral council that will organise elections for the next decade. Victory also gives the winning party authority over the nomination process of judges and executive powers for local administrations.

Two people were injured by gunfire during incidents resulting from a conflict among rival candidates in the northern city of Gonaïves, while two other people who possessed handmade bombs were wounded by police in the town of Limonade.

Heavy gunfire was heard through the weekend in several slum areas in the capital such as Martissant and Fontamara.

Police said they had arrested several people who tried to enter polling centres with guns or were involved in electoral fraud.

Witnesses reported a series of electoral frauds in the capital, Gonaives, Hinche and Jeremie.

"I saw with my own eyes a poll worker fraudulently inserting ballots into the box," said Maxon Maurice, who complained he couldn't find his name on the voters' list in a polling center in the capital. Officials at the polling center denied the allegation.

Haiti, the poorest country in the Americas, held a presidential election in February, its first election since then-President Jean-Bertrand Aristide was ousted by a bloody rebellion two years earlier. In that vote, Rene Preval was declared the winner after he alleged massive fraud at polling stations.