Niger’s state television station was off the air Saturday after heavy gunfire and explosions were reported overnight around a military base near the capital’s airport, with soldiers also blocking access to the presidential palace, according to residents and security sources.

The cause of the clashes was not immediately clear. Niger’s military urged the public to remain calm and avoid spreading unverified information, saying defense and security forces had been mobilized.

“Given the current events, let us remain calm and avoid sharing unverified information,” the military said on its official social media accounts.

A local resident told Agence France-Presse (AFP) that heavy gunfire and explosions could be heard around Air Force Base 101, located inside the international airport complex. Several other residents reported hearing sustained bursts of gunfire overnight and into Saturday morning.

The first shots were heard around 1:00 a.m. local time and continued until daybreak, according to a video posted online by a local journalist showing the area around the airport. Another resident said he heard bursts of gunfire around 7:00 a.m.