Ministries next to the presidential palace in Niamey have also been blocked off, according to Reuters news agency.
Ministries next to the palace have also been blocked off, and staff inside the palace have not been able to access their offices, presidency and security sources said. But there was calm elsewhere in the capital, Niamey.
An official in the presidency said staff inside the palace did not have access to their offices.
It was not immediately clear whether Bazoum was inside or what was happening but Niger’s presidency said in a statement on Wednesday that Bazoum and his family were well.
The presidency added that some members of the presidential guard had started an “anti-republican” movement “in vain” and that the army was ready to attack them if they did not come to their senses.
Bazoum was elected president in a 2021 election that was the first democratic transition of power in a state that has witnessed four military coups since independence from France in 1960.
There have been four military takeovers in neighbouring Mali and Burkina Faso since 2020.
Those coups were spurred in part by frustrations over authorities’ failure to stem a rebel uprising blighting the Sahel region – which includes Niger – that was once derided as the “coup belt”.
There was also a thwarted coup attempt in Niger in March 2021, when a military unit tried to seize the presidential palace days before Bazoum who had just been elected, was due to be sworn in.
Wednesday’s events came less than a month after Bola Tinubu, Nigeria’s president and new chair of the Economic Community of West African States (ECOWAS), called for swift action against insecurity and coups which he said had reached an “alarming proportion”.
Niger is a key ally to Western powers seeking to support local troops fighting a conflict which took root in Mali in 2012 and has spread to neighbouring countries including Burkina Faso and the southern coastal states.
France moved troops to the country from Mali last year after its relations with the military government there soured – an emerging pattern in former French colonies in the region.