Violence has erupted in the Haitian capital as security forces clashed with protesters demanding long-delayed elections and the resignations of the prime minister and the president.

At least one person was killed in the capital Port-Au-Prince late on Saturday, as police fired tear gas at protesters who burned tyres and blocked streets.

"The victim was in his thirties. We have not yet identified him, but he was not participating in the demonstrations," police spokesman Garry Derosiers told the AFP news agency.

The clashes reportedly broke out after hundreds of youth tried to storm through a police barricade and enter the presidential palace.

The unrest followed a demonstration on Friday in which UN peacekeeping troops opened fire on a crowd marching through the capital, set tyres on fire and skirmished with troops and police.

Demonstrations spread to other towns, including Gonaives and Cap-Haitien.

Excessive force

The UN peacekeeping mission in Haiti said it would investigate allegations its troops used "excessive force" in Friday's clashes.

"[We] immediately opened an investigation to establish the facts," the UN body said in a statement.

President Michel Martelly had earlier said his prime minister, Laurent Lamothe, was ready to resign to help end the country's political impasse, but stopped short of saying when this might happen and whether he would leave too.

Martelly has been accused by opposition groups of returning Haiti to dictatorial rule, after repeatedly delaying elections expected since 2011.

Martelly and Lamothe have blamed six opposition senators for blocking the vote. The senators say the legislation is unconstitutional and favours the government.

Source: Al Jazeera and agencies