Explosions and gunfire have been heard coming from the airport in Niger's capital, Niamey, residents have told the BBC.
"I heard the first gunshots at 06:00 (05:00 local time) while I was at the mosque. But the current situation is under control," one person said.
The gunfire, which lasted for two hours, came from the entrance to the airport, a witness told the AFP news agency.
Niger has been fighting a militant Islamist insurgency for a decade and in January suspected jihadists launched an attack on the same airport . Like its neighbours, Burkina Faso and Mali, Niger is run by a military junta that came to power in part because of the failure to deal with the violence.
Residents have told the BBC that Thursday's attack was repelled by the army, which is now hunting down the fleeing assailants who reportedly abandoned their weapons.
The authorities have not yet commented and no group has said it was responsible. But an affiliate to the Islamic State group said it had carried out January's assault.
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