President Francois Bozize of Central African Republic has said he is ready to form a national unity government with rebels, as they continue their advance towards the capital Bangui.
After a meeting with African Union chairman Thomas Boni Yayi, Mr Bozize said he would hold peace talks with rebels in Gabon, and would step down when his term ended in 2016.
The rebels told the BBC they would consider the president's offer. They had pledged to depose Mr Bozize unless he negotiated with them, but have also said that it is not their aim to enter government themselves.
Government troops have reportedly pulled back to Damara, 75km from the capital, in the face of the rebel advance.
The BBC reports the rebels insist that they do not want to take over, but are seeking a peaceful democratic transition. But such a transition is unlikely.
Earlier, the Seleka rebel alliance entered the city of Sibut after the army withdrew on Friday evening.
A BBC correspondent said there was no fighting when rebels entered Sibut on Saturday. The city is about 150km from the capital, Bangui.
Seleka accuses Mr Bozize of failing to honour a 2007 peace deal under which fighters who laid down their arms were meant to be paid. Their campaign began a month ago.
More troops from the Central African Multinational Force arrived in CAR on Saturday to reinforce a contingent already there.