The President of Burkina Faso, Roch Kaboré, has reportedly been detained by mutinying soldiers.
Some troops in the West African nation have demanded the sacking of military chiefs and more resources to fight Islamist militants.
Gunfire had been heard overnight near the presidential palace and at barracks in the capital, Ouagadougou.
The government on Sunday denied suggestions of a military coup or that the president was under arrest.
President Kaboré was detained at a military camp by mutinying soldiers, foreign media reports say.
Video from the capital appears to show armoured vehicles – reportedly used by the presidency – peppered with bullet holes and abandoned in the street.
Mobile internet services have been disrupted, though fixed-line internet and domestic wi-fi are working. Soldiers have also surrounded the state television headquarters and there was no live programming on Monday.
BBC reporter Simon Gongo says a sense of normality has returned to the streets. No further shooting can be heard, and people and cars are moving through the city.
A crowd has gathered in front of the president’s private residence, he says, wanting to understand what happened during the night.
With no official comment from the military or the government, people are anxiously waiting for an official statement on the situation, our reporter says.
On Sunday, hundreds of people came out in support of the soldiers and some of them set fire to the ruling party’s headquarters. A night-time curfew has since been imposed.
The French embassy in the capital has issued a statement saying the situation remains confused, and advising French citizens not to go outside unnecessarily, and never at night. French schools will stay closed and two Air France flights have been cancelled, it said.
The president’s location is unknown, but AFP news agency quoted security sources as saying that he and other government ministers are at the Sangoulé Lamizana barracks in the capital.
There has been no communication from President Kaboré himself since Sunday night, when he posted to social media congratulating the national football team on their win in an Africa Cup of Nations match.
The unrest comes a week after 11 soldiers were arrested for allegedly plotting a coup.
But discontent has been growing in Burkina Faso over the government’s failure to defeat an Islamist insurgency in the country since 2015.
That escalated to new highs in November, when 53 people, mainly members of the security forces, were killed by suspected jihadists. And on Saturday, a banned rally to protest against the government’s perceived failure led to dozens of arrests.
Similar troubles in neighbouring Mali led to a military coup in May 2021 – one that was broadly welcomed by the public.
In Burkina Faso, mutinying soldiers made several demands, including the removal of the army’s chief of staff and the head of the intelligence service; more troops to be deployed to the front line; and better conditions for the wounded and soldiers’ families.
On Sunday, Defence Minister Gen Barthélémy Simporé downplayed previous rumours of the president’s capture, and the nature of the unrest at large.
State television, meanwhile, had characterised the sound of gunfire at military barracks as the actions of a small few disgruntled soldiers rather than a widespread fight or coup attempt.