The Malian government signed a peace agreement with some northern armed groups on Sunday but the main Tuareg rebel alliance asked for more time to consult its grassroots.
The deal, hammered out in eight months of tough negotiations in neighbouring Algeria, provides for the transfer of a raft of powers from Bamako to the north, an area the size of Texas that the rebels refer to as "Azawad".
The Tuareg rebel alliance that includes the National Movement for the Liberation of Azawad said it had asked for a "reasonable delay" for consultations before signing.
"An agreement that has not been shared with the people of the region has little chance of being implemented on the ground," an alliance representative said.
But a spokesman for the Algerian mediators who helped broker the agreement expressed optimism that the rebel alliance would sign soon.
"Their presence here means that they accept the agreement," the spokesman said, adding that the "negotiations are at an end."
A spokesman for the armed groups that did sign hailed the agreement as "an essential document for restoring peace and reconciliation".
"We have undertaken to respect the spirit and the letter of it," Harouna Toureh said.
"We will do all we can so that the agreement comes to life and allows all the peoples of the region to rediscover one and another and live together, as they did in the past, in brotherhood and solidarity."
Militants linked to Al-Qaeda seized control of northern Mali for more than nine months until a French-led military intervention in 2013 that partly drove them from the region.
Jihadist groups were not invited to the Algiers talks.