Capt Camara (Left) wants Burkina Faso's leader (Right) to decide his fate
Guinea's military leader Capt Moussa Dadis Camara has postponed an announcement on whether he will stand in next year's presidential election.
The African Union had given him until midnight on Saturday to formally promise he would not participate.
Capt Camara says he wants the region's appointed mediator, Burkina Faso's leader, to decide his country's future.
The crisis was triggered last month when troops opened fire on protesters, angered at rumours he intended to run.
Human rights groups say some 157 people died but the junta puts the toll at 57.
Soldiers allegedly raped and sexually abused women during the crackdown, and the International Criminal Court (ICC) has opened an investigation into the deaths.
On Saturday, the West African states - through the 15-member regional body Ecowas - imposed an arms embargo on Guinea in protest at the "atrocities".
The AU said it backed Ecowas's move and pressure would be maintained on the mineral-rich nation, where Capt Camara seized power in December within hours of the death of long-time leader Lansana Conte.
After the coup Capt Camara promised to lead a transitional government and hand power back to civilians after an election scheduled for January 2010.
"Legally speaking, the deadline has expired but politically, we are still working to put pressure on the junta," AFP news agency quotes the AU Peace and Security Commissioner Ramtane Lamamra as saying.
"It's the result that matters most."
Mr Lamamra said the AU would wait to hear back from Burkinabe President Blaise Compaore about the junta's position.
"If he tells us that they are sticking to their guns, then sanctions will be enforced," Mr Lamara said.
But Guinea's Foreign Minister Alexandre Cece Loua told AFP sanctions would not "solve the Guinean question".
"We must seek a way to get the parties around the negotiating table," he said.
Earlier this month, Mr Compaore invited all parties in the crisis to Ouagadougou for talks - but the proposal was rejected by opposition groups, who want Capt Camara to stand down first.