At least 34 people were killed and 17 injured in northern Haiti late on Saturday after a bus crashed into a parade of pedestrians, the country's civil protection authorities said on Sunday.

The bus, which was coming from Cap Haitien to the capital Port-au-Prince, crashed into a "rara" parade in the town of Gonaives in the northern part of the country, authorities said.

Rara parades are groupings of musicians playing traditional instruments who are often joined by passers-by.

It was not immediately clear what caused the accident. The driver and passengers on the bus were being held at the police station, said Patrick Cherilus, a Civil Protection spokesman for the department of Artibonite.

After the accident, other musicians and people in the parade began hurling rocks at the bus and passing vehicles, injuring other people, said Albert Moulion, the Ministry of the Interior's spokesman.

Haitian roads are dangerous and chaotic, with few rules observed by pedestrians, motorcyclists and drivers.