At least 16 people were killed early Tuesday in the Haitian capital after a man on top of a musical group's Carnival float was shocked by high-voltage wires above the street, setting off a panic in which dozens of people were trampled, officials said.

The accident occurred as thousands of people filled the streets of downtown Port-au-Prince for the raucous annual celebration. Video from the scene showed sparks coursing from the wire after a singer from the Haitian hip-hop group Barikad Crew was jolted by the overhead power line as the float passed beneath it. The cable appeared to have shocked several others as well.

Prime Minister Evans Paul said 16 people were confirmed dead and 78 were injured. His statement conflicted with earlier reports on the number of casualties. Nadia Lochard, a coordinator for the Department of Civil Protection, had said at least 20 people were killed.

Paul declared three official days of mourning for the impoverished Caribbean country. Haitian officials canceled Tuesday's third and final day of Carnival events and announced a state funeral and vigil on Saturday for the victims.

The singer who was hit by the power cable, a man known by the stage name Fantom, was expected to survive, according to a doctor who spoke to radio station Zenith-FM. The information could not be verified immediately.

Dr. Joel Desire, a doctor at General Hospital, said most of those killed appeared to have been trampled to death as the crowd surged away from the Carnival float, one of 16 in the downtown parade.

Witnesses said panic ensued when people jumped off the float to avoid being electrocuted.

"I saw the wire falling and sparks and I started running for my life," said Natacha Saint Fleur, a 22-year-old who was near the float at the time.

A dazed Carlhenry Belan, who injured his foot in the stampede, said the crowd seemed to surge all at once. "I saw the spark and I saw people running so I did too," the 25-year-old said as he was being treated at the General Hospital.

Video from the scene shows Haitian ambulance crews racing through the crowds in the pre-dawn darkness with victims on stretchers. Hundreds of people crowded around the hospital, carrying victims or looking for information about family and friends amid a chaotic scene. Some men and women wailed as people were declared dead and the hospital's morgue soon overflowed.

Communications Minister Rothchild Francis said the government was working to assist victims. First lady Sophia Martelly visited some of the injured but left the hospital.

It is a common practice in Haiti and elsewhere to have someone positioned atop a parade float to move low-hanging power lines. In Brazil, officials said three people were killed early Tuesday when they were electrocuted while standing atop a Carnival float that hit a power line on the outskirts of Rio de Janeiro.