Burkina Faso's army has reached the capital, Ouagadougou, to seek the surrender of the elite presidential guard who staged a coup last Thursday
Negotiations between army chiefs and the presidential guard are under way, security sources said.
Both the president and the prime minister have been released.
Coup leader Gen Gilbert Diendere says he will step aside once regional leaders endorse a plan including an amnesty for the coup plotters.
Prime Minister Isaac Zida was seized by the presidential guard in last week's coup. France's ambassador to Burkina Faso, Gilles Thibault, has also tweeted that interim President Michel Kafando, who was arrested last Wednesday, has been released from house arrest and is now at the ambassador's residence.
Gen Diendere seems to be backed into a corner by international and national pressure, and on Monday thousands gathered to celebrate what they believed was his defeat, says the BBC's Maud Jullien in Ouagadougou.
But in an interview with the BBC, the general said he would only step aside once an agreement proposed by West African leaders was confirmed.
The proposed deal would give him and his troops full amnesty, and allow candidates of former ruler Blaise Compaore to run for presidency in November.
Speaking from a secret location, Gen Diendere said: "Ready to surrender? We are not there yet… We wish to continue the discussions and we say to all that we are ready to implement Ecowas' [West African regional group’s] decisions."
He also apologised to the population, saying an apology was "the least we could do".
The Ecowas plan should be discussed by West African heads of state in Nigeria later on Tuesday.
The presidential guard is loyal to ousted President Compaore. They installed Gen Diendere as new leader last week. Since then, at least 10 people have been killed and more than 100 injured in clashes.
Burkina Faso's army ordered the presidential guard to disarm before it marched on the capital.
"We must now secure the surrender of the [coup leaders] without gunfire or bloodshed," Col Serge Alain Ouedraogo, of the Burkinabe police, told AFP news agency.
Ecowas' plan includes the return to civilian government, an amnesty for the soldiers behind the coup and elections by the end of November.
But on the streets, there was resentment at the proposals, in particular the amnesty.
"We have no need of Ecowas here, nor the international community," said one man protesting against the coup.
Gen Diendere, who was the chief of staff to Blaise Compaore, led the coup a month before elections had been due in the landlocked country.
International pressure has been building, with former colonial power France warning of "consequences" if coup leaders did not lay down their weapons.