Explosions and gunfire were heard early on Thursday at the airport in Niger's capital, Niamey, residents have told the BBC.
'I heard the first gunshots at 06:00 local time (05:00 GMT) while I was at the mosque. But the current situation is under control,' one person said.
Gunfire, which lasted for two hours, emanated from the entrance at the Diori Hamani international airport, a witness told AFP.
Niger has been fighting an Islamist insurgency for a decade, and in January a suspected jihadist group 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 partly because of a failure to curb the violence.
Residents 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 of the Islamic State group said it had carried out January's assault.
Niger's defence ministry said that in January the attack injured four military personnel and killed 20 attackers.
At the time, Niger's military government head thanked Russia for helping foil the attack and accused the presidents of France, Benin and Ivory Coast of backing those responsible. He did not give details of what help Russia had provided, or provide any evidence to support his accusations against the other countries.
In recent weeks, authorities in Niger have demolished neighbourhoods near the airport, citing "terrorist risks". They have also extended the airport's perimeter fence and installed more than 350 surveillance cameras, AFP reports.
