Last week, ethnic Tuareg captured about 33 Malian soldiers.
The attack occurred in a cross-border region where it is thought that two kidnapped Austrian tourists are being held by the Algeria-based al-Qaeda in the Islamic Maghreb group.
The Tuareg group that is holding the soldiers and Malian officials are expected to meet in Libya for talks on Wednesday or Thursday.
A source close to the mediators said a Malian government delegation and a team lead by Hama Ag Sid-Amey, the father-in-law of the rebel leader Ag Bahanga, are due in the Libyan capital, Tripoli.
Mali's foreign minister has said forces allied to Ag Bahanga "attacked military convoys and planted landmines, with the help of neighbouring Tuareg forces" last week.
The group captured the government troops during clashes in northern Mali on March 20. Eight people, including five civilians, were killed by the mines.
After an uprising in May 2006, many of Mali's Tuaregs made an agreement with the government in 2007, with Algerian help, and in exchange for aid to develop their territory.
But Ag Bahanga refused to go along with the peace deal agreed by the majority of the tribes.
The Malian government believes his group is co-operating with fighters based in Niger to launch attacks.