Gunfire and explosions were reported early Thursday near Diori Hamani International Airport in Niger's capital, Niamey, according to residents and security sources, in what appeared to be a renewed security incident at one of the country's most sensitive installations.

Witnesses said the first bursts of gunfire were heard around 6:00 a.m. local time (0500 GMT) and continued intermittently for nearly two hours, with the sounds originating near the airport entrance and adjoining military facilities. 

Security forces later moved to seal off the area.

"I heard the first shots around 6 o'clock. The shooting was coming from the airport entrance," one resident told AFP, adding that the gunfire was still ongoing later in the morning. Another resident confirmed hearing sustained exchanges near the same location.

Authorities had not issued an immediate statement on the incident, and there was no claim of responsibility at the time of reporting.

The airport has previously been the target of militant activity. In January, Islamic State in the Sahel (EIS) claimed responsibility for an attack on the facility, which Nigerien authorities said was repelled by government forces with support from allied troops. 

That assault targeted areas including air command infrastructure and drone assets, according to the group's statement.

Following the January attack, authorities demolished thousands of informal structures in surrounding neighborhoods, saying the area had been infiltrated by militants used to stage operations.

Further details on Thursday's incident were not immediately available, and officials have yet to confirm the extent of any damage or casualties.