Mali’s interim President Bah Ndaw and Prime Minister Moctar Ouane have officially resigned, according to the AFP news agency.
Mr Ndaw and Mr Ouane have been detained since Monday evening at a military camp outside the capital, Bamako.
The officer who led last year’s coup and became vice-president of an interim government, Col Assimi Goïta, accused them of failing in their duties and seeking to sabotage the country’s transition.
Reports of their resignations come as West African mediators visit the country hoping to organise their release from military detention.
On Tuesday a military colonel – who was the vice-president in the transitional government – accused President Bah Ndaw and Prime Minister Moctar Ouane of sabotaging the transition.
The two men have been held at a military camp since Monday.
The Ecowas team has an extremely difficult mission.
Led by the former Nigerian President Goodluck Jonathan, it hopes to get the ousted president and prime minister released from military detention as soon as possible.
But beyond that it is not clear what it can achieve now that Colonel Assimi Goïta is running the country and looks set to name a new prime minister.
Ecowas and other international bodies could impose sanctions against those behind the coup.
But they will be aware that that could further complicate Mali’s road to elections and the promised return to civilian rule early next year.
The UN Security Council is due to discuss the political crisis later on Wednesday.