Disgruntled soldiers sealed off access to Ivory Coast's second largest city Bouake on Saturday, soldiers and residents said.
Protests over a pay dispute stretched into a second day in the country despite government warnings of harsh punishments.
The revolt began in Bouake early on Friday before spreading quickly, following a pattern similar to a mutiny in January by the same group that paralysed parts of the West African state and marred its image as a post-war success story.
Mutinying soldiers in Bouake went a step further on Saturday, blocking roads leading north and south out of the city.
"We do not want to negotiate with anyone," said Sergeant Seydou Kone, one of the leaders of the uprising. "We're also ready to fight if we are attacked. We have nothing to lose."
Bouake residents said shops remained closed as soldiers, many of them wearing balaclavas, fired their weapons in the air and patrolled the streets in stolen cars.
Kone said the mutineers were also active in the commercial capital Abidjan and the towns of Korhogo, Daloa, Man and Bondoukou. A Korhogo resident confirmed gunfire there and said access to the main military camp had been blocked.
On Friday, Military Chief of Staff General Sekou Toure threatened the soldiers with "severe disciplinary sanctions" if they did not end the revolt.