Burkina Faso's military has taken to the airwaves to declare it now controls the country in a coup mounted weeks before elections.
A former aide to ex-president Blaise Compaore, who was ousted in a popular uprising last year, was named the new head of state.
In an interview with The Associated Press, General Gilbert Diendere said the scheduled October 11 election date was too soon.
At least one person was killed when the presidential guard opened fire with live ammunition to disperse crowds protesting the coup, witnesses said.
Burkina Faso's land and air borders were closed and a 7pm to 6am curfew was imposed.
The coup - the country's sixth since it won independence from France in 1960 - unfolded overnight. The country's interim president Michel Kafando and prime minister Isaac Zida were arrested at the presidency on Wednesday evening.
A communique read on state TV and radio early on Thursday by an army lieutenant colonel criticised the electoral code, which blocked members of Mr Compaore's party from taking part in the elections. Anyone who supported the ex-president's bid to amend the constitution so he could seek another term was also banned from running.
The coup leaders later announced that General Diendere, who had been head of the elite presidential guard under Mr Compaore and was his long-time aide, was now in charge.
General Diendere also criticised the electoral code that barred Mr Compaore's supporters from taking place. He vowed that elections would go forward but not on the timeframe that was set to end a period of transition after Mr Compaore was ousted late last year after 27 years in power.
"Today it seems to me that the October 11 date is too soon to hold the election," General Diendere said. "It's not at our level to speak of Compaore's return. We want to stabilise the country and hold elections."
"The United States strongly condemns any attempt to seize power through extra-constitutional means or resolve internal political disagreements using force," US State Department spokesman John Kirby said in a statement.
Speaking on state TV and radio early Thursday before a blue background, Lieutenant Colonel Mamadou Bamba said the country's transitional government was dissolved and the interim president was no longer in power. He announced the beginning of a "coherent, fair and equitable process" that would lead to inclusive elections.
Burkina Faso hosts French special forces and serves as an important ally of both France and the United States in the fight against Islamic militants in West Africa. While Burkina Faso has largely been spared from extremist violence, a Romanian national was abducted in April, and a Mali-based jihadi group claimed responsibility.