Alassane Ouattara, Ivory Coast's internationally recognised president, has rejected the African Union's nomination of an envoy to negotiate an end to the crisis in the country, questioning his impartiality.
The AU on Saturday appointed Jose Brito, Cape Verde's former foreign minister, to oversee talks meant to result in incumbent Laurent Gbagbo stepping down in favour of Ouattara, who would lead a unity government to end a crisis that has pushed the country to the brink of war.
But Ouattara's camp overnight complained it had not been consulted on the AU nomination, adding that Brito was unsuitable as he had personal and professional relations with Gbagbo and was not a former president, as had been expected.
A spokesman for Gbabgo's camp was not immediately available.
The AU has been seeking a peaceful solution to the row over the November 28 election, which has led to violence that has killed hundreds and forced over a million people from their homes, raising the prospect of a resumption of the 2002-2003 civil war.
But few have pinned their hopes on the body making a breakthrough as a series of previous envoys have failed, and both sides are deeply entrenched, with Ouattara confined to a hotel protected by UN peacekeepers and Gbagbo accusing foreigners of meddling in his country's internal affairs.
The fiercest fighting has seen insurgents take control of swathes of northern Abidjan in Abobo neighbourhood, one of several pro-Ouattara areas the UN has accused Gbagbo's forces of firing heavy weapons into. His camp denies the charge.
Residents in Abobo said two shells were fired into the neighbourhood on Sunday morning but it was not clear who was involved.
Residents in Angre, a upper-class neighbourhood near Abobo, also said there had heard clashes there late on Saturday. Rebels, who have controlled the north of the country since the 2002-03 civil war and declared allegiance to Ouattara, have also pushed south in the west of the country in the latest turmoil.