The move comes less than a week after Nigerian media reported a foiled coup plot -- although the government and military denied the reports.

"I have approved changes in the hierarchy of our armed forces to further strengthen Nigeria's national security architecture," President Bola Tinubu said in a brief statement.

While the government has officially denied that there was a coup plot, a senior administration official told AFP: "Normally when such a thing happens, it means there is a gap in intelligence. No leader would accept that."

General Christopher Musa, who was appointed chief of defence staff in 2023, had overseen multiple high-profile summits in the capital, Abuja, drawing together defence officials from west Africa and the wider continent.

However, the country's long-running fight against Boko Haram and Islamic State West Africa Province militants is still raging in the northeast and researchers have warned of an uptick in jihadist attacks this year.

- Officers arrested -

The military is stretched across multiple fronts, fighting armed gangs known as "bandits" in the northwest as well as separatists in the southeast.

"Military leadership reshuffle is a very normal and regular procedure in Nigeria," Confidence MacHarry, a security analyst at Lagos-based consultancy SBM Intelligence, told AFP.

At the same time, the "military has failed to convincingly deny" the alleged coup plot.

"This shake-up could thus be a means of taking the wind out of the sail of coup plotters" who reportedly complained about career stagnation "or as a means of punishment for the military chiefs for their failure to improve security", he added.

General Olufemi Oluyede, appointed chief of defence staff to replace Musa, hails from Tinubu's home region of southwest Nigeria.

Oluyede had been serving as chief of army staff since last year.

The chief of intelligence has not been replaced.

Over the weekend, Nigerian outlets Sahara Reporters and Premium Times reported that at least 16 officers were planning to overthrow Tinubu.

The military announced earlier this month that 16 officers had been arrested over "issues of indiscipline".

Citing defence sources, the newspapers said the arrests were in fact linked to a coup plot.