An explosion on a city bus killed 18 passengers and burned another 18 in downtown Panama City on Monday, interior minister Olga Golcher said.
"There was an explosion and everything filled with smoke," said survivor Rosa Marin.
"Those who could do so jumped out the windows," she said.
Fire chief Mario Puertas said the bus had no emergency exit.
Santo Tomas hospital director Gerardo Victoria said 12 of the burn victims were adults and six were children.