African leaders on Sunday gave the junta in Niger one week to cede power or face the possible use of force, and slapped financial sanctions on the putschists, after the latest coup in the jihadist-plagued Sahel region raised alarm on the continent and in the West.

At an emergency summit in Nigeria, the Economic Community of West African States (ECOWAS) regional bloc demanded Bazoum be reinstated, within a week.

Otherwise, the bloc said it would take "all measures" to restore constitutional order.

"Such measures may include the use of force for this effect," it said in a statement, adding that ECOWAS defence chiefs were to meet on Sunday.

"No more time for us to send a warning signal… It’s time for action", said Bola Tinubu, president of Nigeria and ECOWAS chairman.

It was not immediately clear how the 15-member ECOWAS could use force. Last year, the bloc agreed to create a regional security force to intervene against jihadists and prevent military coups, but details on the force and its funding have not been outlined.

The bloc also slapped financial sanctions on the junta leaders and on the country, freezing "all commercial and financial transactions" between member states and Niger, one of the world's poorest nations, often ranking last on the UN's Human Development Index.