The leaders of a coup in Niger on Monday defied an ultimatum to restore President Mohamed Bazoum to power.
Hours after thousands gathered in the capital Niamey in rallies backing the soldiers and denouncing possible foreign intervention, military commanders sealed off the country's airspace until further notice.
"In the face of the threat of intervention that is becoming more apparent ... Nigerien airspace is closed," a junta representative said in a statement on national television.
He said forces had been put on alert in two central African countries in preparation for an intervention but did not give details.
"Niger's armed forces and all our defence and security forces, backed by the unfailing support of our people, are ready to defend the integrity of our territory," the spokesman said.
Chance
The Economic Community of West African States (Ecowas) gave the military officers leading the coup in Niger until Sunday night to release Bazoum from his residence, where members of the presidential guard have been holding him since 26 July.
With the deadline passed, Ecowas defence chiefs say they have agreed a possible military action plan, including when and where to strike against General Abdourahmane Tchiani's junta.
On Friday in Abuja at the close of a three-day meeting, Abdel-Fatau Musah, the Ecowas commissioner for political affairs, peace and security, said the decision of when and where to strike will be made by heads of state.
"All the elements that will go into any eventual intervention have been worked out here, including the resources needed, the how and when we are going deploy the force," he added.
But any military intervention could be complicated by a promise from juntas in neighbouring Mali and Burkina Faso to come to Niger's defence if needed.
On Monday, as France's foreign ministry formally discouraged any travel to Niger, Burkina Faso or Mali, they highlighted that pledge by sending a delegation to Niamey led by Abdoulaye Maïga, the Malian Minister of State, Minister of Territorial Administration and Government Spokesman.
"The delegation is to demonstrate the solidarity of the two countries with the brotherly people of Niger, the Malian Armed Forces in a statement.
Algeria and Chad, which are not part of Ecowas but share borders with Niger, have both stated they will not participate in any military operation.
"We categorically refuse any military intervention," Algerian President Abdelmadjid Tebboune said in a television interview on Saturday evening, adding that such action would be " direct threat to Algeria.
Whatever option the 15 nations in Ecowas choose, there is likely to be a risk of further conflict in a zone where groups linked to Islamic State and al Qaeda operate.
On Monday, Italy's Foreign Minister Antonio Tajani called for more talks to avoid military intervention.
"The only way is the diplomatic one," Tajani told La Stampa newspaper. "I hope that the ultimatum of Ecowas will be extended today."
