Niger's new military ruler said Saturday a transition of power would not go beyond three years, and warned that any attack on the country would not be easy for those involved.

"Our ambition is not to confiscate power," General Abdourahamane Tiani said in a televised address. Any transition of power "would not go beyond three years", he said.

But he added: "If an attack were to be undertaken against us, it will not be the walk in the park some people seem to think."

His warning came as a delegation from West African bloc ECOWAS arrived in the country for a final diplomatic push before deciding whether to take military action against the country's new military rulers.

They met ousted president Mohamed Bazoum, who has been held with his family at the president's official residence since officers from his personal guard deposed him and seized power on July 26.

ECOWAS defence chiefs met this week to fine-tune details of a potential military operation to restore Bazoum if ongoing negotiations with coup leaders fail.