West African leaders meeting in Ghana's capital on Thursday imposed a travel ban and asset freeze on Guinea's army rulers, the bloc's toughest response yet to a spate of coups in the region.
The ECOWAS sanctions also extend to family members of the junta leaders.
The bloc also demanded a quick return to civilian rule.
The demand came after a summit of the 15-nation regional group to decide how to respond to the September 5 ouster of president Alpha Conde by special forces troops commanded by Col. Mamady Doumbouya.
The bloc also piled more pressure on Mali’s transitional government, demanding they stick to an agreement to organize elections next February. It announced sanctions on those it said were frustrating efforts for a return to constitutional rule.
In May, Mali junta leader Colonel Assimi Goita staged another coup, deposing a transitional administration in which he was vice president.
He has pledged to stick to the old transition schedule but his government has been accused of dragging its feet on efforts to achieve civilian rule.
"Because they (ECOWAS head of states) are concerned about the slow progress in the preparation of the election, they decided to impose sanctions on those who have negative impact in the implementation of the transition, on the transition electoral process," Brou said.
Guinea's junta was due to hold its last day of consultations on the future of the country in Conakry on Friday. Alpha Conde's ouster has received political backing at home but courted international condemnation.
There was no immediate reaction from Mali on ECOWAS' new measures.