A crowd stampeded after leaving a New Year's fireworks show in Ivory Coast's commercial centre, killing 61 people - many of them children - and injuring more than 200, rescue workers said.
The death toll was expected to rise, the officials said.
Thousands had gathered at the Felix Houphouet Boigny Stadium in Abidjan's Plateau district to see the fireworks. After the show, the crowds poured onto the Boulevard de la Republic by the Hotel Tirama at about 1am (2pm Tuesday, NZ time), said Colonel Issa Sako of the fire department rescue team.
"The flood of people leaving the stadium became a stampede which led to the deaths of more than 60 and injured more than 200," Sako told Ivory Coast state TV.
Most of those killed were between 8 and 15 years old, he said.
Desperate parents went to the city morgue, the hospital and to the stadium to try to find children who are still missing.
Mamadou Sanogo was searching for his nine-year-old son, Sayed.
"I have just seen all the bodies, but I cannot find my son," said a tearful Sanogo. "I don't know what to do."
President Alassane Ouattara and his wife visited some of those hospitalised and he pledged that the government would pay for their treatment, his office said.
The government organised the fireworks to celebrate Ivory Coast's peace, after several months of political violence in early 2011 following disputed elections. It was the second year that Abidjan had a New Year's fireworks display.
Hours after the stampede, soldiers patrolled the site, where victims' clothes, shoes and other debris littered the street.
State TV showed traumatic scenes: a woman sobbed in the back of an ambulance; another was bent over on the side of the street, apparently in pain; and another, barely conscious and wearing only a bra on her upper body, was hoisted up by rescuers.
There were also scenes of small children being treated in a hospital; one boy grimaced in pain and a girl with colored braids in her hair lay under a blanket, with one hand bandaged.
Ivory Coast is the world's largest cocoa producer, growing more than 37 per cent of the world's annual crop of cocoa beans, which are used to make chocolate.