Coup leader Colonel Mamady Doumbouya -- who was sworn in as president in the West African state last October -- has promised to restore civilian rule after a transitional period.

But he has so far resisted international pressure to commit to a date.

The head of Doumbouya's interim government, Mohamed Beavogui, last week announced that a national conference aimed at finding a path forward for the country would be held from March 22.

He stressed the need "to forgive and move forward" in the nation of 13 million people, which has a history of authoritarian rule and political violence.

But on Friday, 12 leading Guinean rights groups said in a joint statement that they would skip the conference unless the junta clarified what they termed "undefined and imprecise aims" for the talks.

They also demanded that the junta set up a reconciliation commission after the conference, as a condition for their participation.

Several African countries have set up such panels to shed light on atrocities committed during periods of repression or war, with South Africa's post-apartheid Truth and Reconciliation Commission being the most notable example.

Guinea's strongman Doumbouya deposed elected president Alpha Conde in a putsch on September 5, defying broad diplomatic condemnation of the coup.

Conde, 84, had drawn fierce opposition after he pushed through a new constitution in 2020 that allowed him to run for a third presidential term.

Dozens of protesters were killed in nationwide unrest ahead of the September coup, and dozens of opposition activists were also arrested.

Among the signatories to Friday's statement were groups representing victims of massacres committed under other former Guinean leaders.

One group represents the victims of a notorious incident in 2009, for example, when soldiers loyal to then military leader Moussa Dadis Camara killed 150 people during an opposition rally in a stadium in the capital Conakry.