Alassane Ouattara's spokesman said his troops had overrun the home of Laurent Gbagbo, who refuses to step down, though his whereabouts are unclear. Heavy weapons fire rocked the city early on Tuesday.

Hours earlier, UN and French helicopters attacked targets around the presidential residence.

Mr Ouattara's representative in Paris, Ali Coulibaly, told France Info radio that Mr Gbagbo was now negotiating his surrender

Mr Gbagbo has refused to leave office even though the Ivorian election commission declared him the loser of November's run-off vote, and the UN certified the result.

Forces loyal to Mr Ouattara, a former International Monetary Fund economist, began a dramatic military offensive last week, sweeping in from the north and west.

About four million civilians have been trapped by days of fighting and looting in Abidjan.

There is no confirmation of reports that pro-Ouattara forces have taken Mr Gbagbo's compound.