Disgruntled soldiers, who demand salary increases and the payment of bonuses, seized Ivory Coast's second-largest city of Bouake on Friday, the West African nation's defence minister said.
The unrest comes weeks after parliamentary elections that had been viewed as a further step towards stability in the West African nation, which emerged from a 2002-2011 political crisis as one of the continent's rising stars.
"It is asked that all soldiers remain calm and return to barracks so that lasting solutions can be found," a statement from the country's Defense Minister Alain-Richard Donwahi read on state-owned television.
An officer at Ivory Coast's military headquarters in the commercial capital Abidjan said reinforcements had been sent to Bouake.
"The situation remains unstable and serious in Bouake ...Some civilians and even active-duty soldiers have started to rally to them," he said.
Hours after the seizure of Bouake, similar mutinies erupted also in Daloa and Korhogo. Karim Sanogo, a student in Daloa, says heavily armed men are parading through town and security forces have abandoned their posts.
Shooting was heard overnight in Bouake as demobilised soldiers seized weapons from police stations and took up positions at entry points into the city, military sources said on Friday.
Heavy gunfire was heard at around 2am before later easing, residents said, and sporadic shooting continued into the late morning.
Residents stayed inside and businesses in Bouake remained closed on Friday morning.
"The city is deserted. Men in balaklavas are patrolling the city on motorcycles or in cars. They aren't attacking residents ... They told us to stay at home," said Ami Soro, a teacher living in the city.
A similar uprising occurred in 2014 when hundreds of soldiers barricaded roads in several cities and towns across the country demanding back pay. The government agreed a financial settlement with the soldiers, who returned to barracks.
Bouake was the stronghold of the rebel-controlled north throughout the country's 2002-2007 civil war. Many of those fighters have been integrated into Ivory Coast's army.
The soldiers, however, say not all the promises made in a 2007 agreement were implemented.