The President of Niger Mamadou Tandja has been detained by troops in a military coup.
At least three soldiers have been killed during an attack on the palace where the president was chairing a meeting, sparking several hours of gunfire in the capital Niamey.
His ministers are also being held.
According to sources in Nigeria the coup is led by Major Adamou Harouna.
Political tension has been high in the west African uranium exporter in recent times over Tanja’s decision to extend his rule, which drew widespread condemnation and international sanctions.
State radio, which had been broadcasting normally, began playing military music indicating something was afoot.