At least 16 people have died and 78 others hurt after a carnival float hit a power line in the Caribbean country of Haiti.

Most of the victims were trampled to death in a stampede after the float struck a high-voltage overhead cable in the capital Port-au-Prince, witnesses said.

Amateur video on social media showed sparks after a singer called Fantom, who was on the float, was jolted by the power line near a stand packed with spectators.

Seven people on the float were electrocuted, and others were trampled to death during the three-day event which coincides with many Mardi Gras carnivals internationally.

Earlier reports indicated around 20 people had died, but it is now reported at least 16 people were killed as a result of the incident.

Prime Minister Evans Paul has declared three official days of mourning.

Haitian officials cancelled the final day of events and announced a state funeral and vigil on Saturday for the victims.

Fantom, part of the hip-hop band Barikad Crew, was among the injured and was expected to survive, according to a doctor.

"I saw the wire falling and sparks and I started running for my life," said Natacha Saint Fleur, a 22-year-old who witnessed the accident.

Haiti's president, Michel Martelly, has expressed his "sincerest apologies" to victims and their families.

Before the event began, Haiti's US embassy warned visitors to be vigilant for robberies, assaults and pick-pockets.

"Carnival can be a fun, yet potentially unsafe place for revellers," its statement said.

Meanwhile, three men were killed in a similar accident in Rio de Janeiro.

Police said they were electrocuted as they pushed a float towards a parade ground and it struck a power cable at Brazil's main carnival.

A sun on the float made of wire touched the power line and sent a fatal electrical charge through the metal frame of the decorated platform, police said.

Authorities cancelled carnival festivities in the Nova Iguacu district after the accident.

Originally posted at 18.30