PORT-AU-PRINCE, Haiti (AP) -- At least 20 people were killed early Tuesday in the Haitian capital when a man on top of a musical group's Carnival float was electrocuted and set off a panic in which dozens of people were trampled, witnesses and 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 shows sparks coursing from the wire after the man apparently tried to move the wire so the float could pass underneath it.

There were conflicting reports on the number of casualties. Nadia Lochard, a coordinator for the Department of Civil Protection, said at least 20 people were killed and 46 were injured.

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.

The float, one of 16 in the downtown Carnival parade, was sponsored by the Haitian hip-hop group Barikad Crew. Some of the victims were instantly electrocuted in a flash of sparks, according to witnesses. Others managed to jump off, causing panic in the crowd.

"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.

Hundreds of people thronged the General Hospital, where many of the victims were taken, some carrying victims and others searching for family members brought by ambulance.

Haitian officials were expected to announce later Tuesday whether they would cancel a second day of Carnival events. Communications Minister Rothchild Francis said the government was working to assist victims. First lady Sophia Martelly visited some of the injured at the General Hospital but left without speaking to reporters.

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.