Mali and Burkina Faso are sending a joint official delegation in a show of solidarity with Niger, which is under the control of the coup leader who toppled the elected government.
"Burkina Faso and Mali are sending a delegation to Niamey," the Malian army said. "The aim: to demonstrate the solidarity of the two countries with the brotherly people of Niger."
The delegation is expected to arrive in Niger on Monday, according to Niger's foreign ministry.
The coup leaders in Niger defied a Sunday deadline from the West African bloc ECOWAS to reinstate democratically elected President Mohamed Bazoum by Sunday midnight or face possible military action.
Mali and Burkina Faso, where the military also took power by force in 2020 and 2022, had warned that they would consider military intervention as a declaration of war.
As the Sunday deadline expired, the junta closed its airspace until further notice, citing the ''threat of military intervention.''
ECOWAS defence chiefs had agreed a possible military action plan, including when and where to strike, if the detained president, Mohamed Bazoum, was not released and reinstated by Sunday.
But the regional group ECOWAS has not made any public comments after the ultimatum expired.
The situation in Niger is getting reactions globally.
The German government warned the coup leaders against acts of violence against detained President Mohamed Bazoum.
Speaking to media representatives in Berlin, Foreign Ministry spokesman Sebastian Fischer made it clear that they are worried about Bazoum.
"And that is why I would like to take this opportunity to once again underline our message to the putschists that they must expect severe personal consequences should anything happen to democratically elected President Bazoum and his family," Fischer said.