Eleven Nigerian military officers were briefly detained in Burkina Faso after their aircraft made an emergency landing in the country, Burkinabè security sources told the BBC.
The Air Force C-130 aircraft entered Burkina Faso's airspace on Monday without authorisation, according to the country's Territorial Administration Minister Emile Zerbo.
In a joint statement, the military governments of Burkina Faso, Mali and Niger said their prompt investigation confirmed the "violation of its airspace and the sovereignty of its member states".
But the Nigerian Air Force (NAF) said a technical problem meant the plane, which was en route to Portugal, had to land in accordance with safety procedures.
The statement added that the crew was "safe and have received cordial treatment from the host authorities". It did not mention whether they had been detained.
