The army officers who have seized power in Burkina Faso said in televised comments on Saturday that toppled junta leader Paul-Henri Sandaogo Damiba was planning a counteroffensive from a "French base".
Damiba "is believed to have taken refuge in the French base at Kamboinsin in order to plan a counter-offensive to stir up trouble in our defence and security forces," they said in a statement read out on national television and signed by Captain Ibrahim Traore, the country's new strongman.
France, the former colonial power in Burkina Faso, denied any involvement.
An hour before the televised comments by the military figures, who overthrew Damiba on Friday, the French embassy issued a statement "firmly denying any involvement of the French army in the events of the last few hours".
The embassy also denied "rumours that Burkinabe authorities have been hosted or are under the protection of French military".
UN Secretary General Antonio Guterres "strongly condemns any attempt to seize power by the force of arms and calls on all actors to refrain from violence and seek dialogue," his spokesman said in a statement Saturday.
"Burkina Faso needs peace, stability and unity to fight terrorist groups and criminal networks operating in parts of the country," the UN statement added.
Damiba himself came to power in a coup in January.
He had installed himself as leader of the country of 16 million after accusing elected president Roch Marc Christian Kabore of failing to beat back jihadist fighters.
With much of the Sahel region battling a growing Islamist insurgency, the violence has prompted a series of coups in Mali, Guinea and Chad since 2020.
According to the new Burkina putschists, the actions by Damiba and the French forces are in response to their willingness "to go to other partners ready to help in the fight against terrorism".
No country was explicitly mentioned but Russia, whose influence is growing in French-speaking Africa, is among the possible partners in question.
France has a military presence in Burkina Faso, with a contingent of special forces based in Kamboinsin which is some 30 kilometres (19 miles) from the capital Ouagadougou.
The situation in Ouagadougou was tense on Saturday, with gunfire and the deployment of soldiers in the streets, raising fears of clashes between Damiba's supporters and the country's new strongmen.
Helicopters hovered above the city and shops that had opened for business in the morning shut their doors.
The European Union and the African Union added their voices to a chorus of global condemnation of the second coup this year in the deeply poor and restive West African country.
"The chairperson calls upon the military to immediately and totally refrain from any acts of violence or threats to the civilian population, civil liberties, human rights," the AU said in a statement, calling for the restoration of the constitutional order by July 2024.
The junior officers who toppled Damiba on Friday said he had failed to fight jihadist attacks in the country.
The European Union warned that the latest coup put in danger efforts undertaken to restore constitutional order by July 1, 2024 and called for the new authorities to respect previous agreements.
"The European Union also deplores the degradation of the security and humanitarian situation in the country," the bloc's foreign policy chief Josep Borrell said in a statement.
The Economic Community of West African States regional bloc "condemned in the strongest possible terms" the latest seizure of power, calling it "inappropriate."
The United States called "for a return to calm and restraint by all actors".
On Friday, pre-dawn gunfire erupted in the dusty and spread-out capital around the presidential palace and culminated in the latest coup.
Damiba accused of failure
Just before 8:00 pm (2000 GMT) on Friday, more than a dozen soldiers in fatigues appeared on the state television and radio broadcaster to announce the removal of Lieutenant-Colonel Paul-Henri Sandaogo Damiba.
They proclaimed 34-year-old Captain Traore in charge.
"Damiba failed. Since he came to power, the zones that were peaceful were attacked. He took power but then he betrayed us," Habibata Rouamba, a trader and activist said on Saturday.
More than 40 percent of the country remains outside government control.
The new leaders swiftly suspended the constitution, sealed the borders, dissolved the transitional government and legislative assembly and instituted a 9:00 pm to 5:00 am curfew.
New strongman Traore was previously head of anti-jihadist special forces unit "Cobra" in the northern region of Kaya.
In the north and east, towns have been blockaded by insurgents who have blown up bridges and attacked supply convoys.
As in bordering countries, insurgents affiliated with Al-Qaeda and the Islamic State group have stoked unrest.
Thousands have died and about two million have been displaced by the fighting since 2015 when the insurgency spread to Burkina Faso, which has since become the epicentre of the violence across the Sahel.
In September, a particularly bloody month, Damiba sacked his defence minister and assumed the role himself.