The West African nations as well as France had urged soldiers in crisis-torn Mali to return to their barracks, after unrest erupted at a key base near the capital.
Mutineering soldiers in Mali on Tuesday detained President Ibrahim Boubacar Keita and Prime Minister Boubou Cisse, one of their leaders said.
He added that the pair had been “arrested” at Keita’s residence in the capital Bamako.
A government official also confirmed to AFP that the duo are in the custody of rebel soldiers.
Earlier, soldiers launched a mutiny from the nearby garrison town of Kati.
Another military official, who also declined to be named, said the president and prime minister were in an armoured vehicle en route to Kati.
In separate statements, the 15-nation regional bloc ECOWAS and France accused troops of “mutiny” at a time of wrenching problems in their country, and warned against any undemocratic change of power.
The Malian government said the soldiers may have “legitimate frustrations” and urged “fraternal dialogue in order to remove all misunderstandings.”
The statements gave no details, but witnesses earlier reported gunfire at an army base in the town of Kati, some 15 kilometres (nine miles) from Bamako, which was then sealed off by troops, an AFP reporter saw.
A soldier told AFP that disgruntled troops had taken over the camp and were holding “several senior army officers.”
An officer at the camp said many soldiers were unhappy with Mali’s political situation, adding: “We want change.”
Reports circulated in Bamako that ministers had also been arrested, but these could not be confirmed.
Convoys of armed men travelling in pick-up trucks – some dressed in military fatigues – also arrived in Bamako on Tuesday and were cheered on by jubilant crowds, an AFP journalist saw.
Meanwhile President Muhammadu Buhari yesterday received briefing from his immediate predecessor, Goodluck Jonathan, on the political situation in Mali as corollary to efforts by West African leaders to restore stability to the country.
Buhari, according to a statement issued by his spokesman, Femi Adesina, thanked Jonathan for what he called “the stamina you have displayed” on the Mali issue, and counseled further consultations with the Chairman of ECOWAS, President Mahamadou Issoufou of Niger Republic.
Buhari and four other ECOWAS leaders had visited Bamako, Mali, last month, followed by a virtual extraordinary summit of the sub-regional body.
Jonathan, who was in Mali from Monday to Thursday last week, recounted his meetings with the stakeholders, including political and religious leaders, Ambassadors of US, France, Russia, Germany, European Union, and other important personalities key to peace and cohesion in the country.
The main opposition group, M5, he said, continued to insist on the resignation of President Ibrahim Boubacar Keita, a position not acceptable to ECOWAS, which insisted only on democratic process in change of power within its jurisdiction.