African leaders on Sunday gave the junta in Niger one week to cede power or face the possible use of force, and slapped financial sanctions on the putschists, after the latest coup in the jihadist-plagued Sahel region raised alarm on the continent and in the West.
In the third coup in as many years to fell a leader in the Sahel, Niger's elected president and Western ally, Mohamed Bazoum, has been held by the military since Wednesday.
General Abdourahamane Tiani, the head of the powerful presidential guard, has declared himself leader.
Bazoum is one of a dwindling group of elected presidents and pro-Western leaders in the Sahel, where since 2020 a jihadist insurgency has triggered coups in Mali and Burkina Faso.
Former colonial ruler France and the European Union have suspended security cooperation and financial aid to Niger following the coup, while the United States warned that its aid could also be at stake.
At an emergency summit in Nigeria, the Economic Community of West African States (ECOWAS) regional bloc demanded Bazoum be reinstated, within a week.
Otherwise, the bloc said it would take "all measures" to restore constitutional order.
"Such measures may include the use of force for this effect," it said in a statement, adding that ECOWAS defence chiefs were to meet on Sunday.
"No more time for us to send a warning signal... It's time for action", said Bola Tinubu, president of Nigeria and ECOWAS chairman.
It was not immediately clear how the 15-member ECOWAS could use force. Last year, the bloc agreed to create a regional security force to intervene against jihadists and prevent military coups, but details on the force and its funding have not been outlined.
The bloc also slapped financial sanctions on the junta leaders and on the country, freezing "all commercial and financial transactions" between member states and Niger, one of the world's poorest nations, often ranking last on the UN's Human Development Index.
Late on Saturday, the junta condemned the ECOWAS summit, saying its aim was to "approve a plan of aggression against Niger, in the form of an imminent military intervention in Niamey".
The intervention would be "in cooperation with African countries who are not members of the regional body and certain Western nations", junta member Amadou Abdramane said on national television.
The president of Chad, which neighbours Niger but is not a member of ECOWAS, attended the summit and then left for Niger's capital.
General Mahamat Idriss Déby Itno was in Niamey "to see what he could bring to solving the crisis," a Chad government spokesman told AFP, adding that he was not mandated by the bloc.
Former Niger president Mahamadou Issoufou, whom Bazoum succeeded as head of state, on Sunday said that he intended to negotiate with the junta to restore Bazoum to the presidency.
"I have undertaken, by various ways, to find a negotiated solution that will allow to free President Mohamed Bazoum and to reinstate him," Issoufou wrote on Twitter, which is being rebranded as X.
In the capital Niamey on Sunday, thousands of people waving Russian and Niger flags rallied outside the national parliament in Niamey in a show of support for the junta.
They then moved on to the French embassy, shouting "long live Putin" and "down with France". Some tried to storm the embassy, but were dispersed with tear gas, an AFP journalist saw.
France condemned the assault on its embassy, warning it would retaliate if its citizens or interests were attacked.
"Should anyone attack French nationals, the army, diplomats and French interests, they will see France respond in an immediate and intractable manner," the French presidency said.
Niger's neighbours and fellow former French colonies Mali and Burkina Faso have both been beset by military coups since 2020, fuelled by anger at the civilian authorities' failure to quash long-running insurgencies by jihadists linked to the Islamic State group and Al-Qaeda.
Tiani said the putsch in Niger was a response to "the degradation of the security situation" linked to jihadist bloodshed, as well as corruption and economic woes.
- Turbulent political history -
After a wave of condemnation for the coup, punitive measures have already begun in the West.
France -- which has 1,500 soldiers in Niger -- said on Saturday it was suspending development aid and budgetary support to the West African nation.
European Union diplomatic chief Josep Borrell meanwhile said the EU would not recognise the putschists, and announced the indefinite suspension of security cooperation with Niger with immediate effect, as well as budgetary aid.
The United States -- which has about 1,000 troops in Niger -- has offered Bazoum Washington's steadfast support and warned those detaining him that they were "threatening years of successful cooperation and hundreds of millions of dollars of assistance".
The African Union condemned the coup and expressed deep concern over the "alarming resurgence" of military overthrows in Africa.
It has had a turbulent political history since gaining independence in 1960, with four coups as well as numerous other attempts -- including two previously against Bazoum.