Fighting erupted when they later entered the key port of San Pedro on their advance from the north against incumbent leader Laurent Gbagbo.

Mr Gbagbo continues to cling to power in the main city Abidjan.

The UN, which recognises Mr Ouattara as winner of November's poll, has voted to impose sanctions on Mr Gbagbo's circle.

They add to economic measures already taken by the EU and African groups.

The UN resolution, drafted by France and Nigeria, imposes a travel ban and assets freeze on Mr Gbagbo, his wife Simone and three of his closest associates.

One million people have fled the violence - mostly from the main city Abidjan - and at least 462 people have been killed since December, according to the UN.

Abidjan remains largely under the control of Mr Gbagbo but Yamoussoukro's capture is a major symbolic victory for the pro-Ouattara forces, the BBC's John James reports from the central city of Bouake.

Yamoussoukro is the capital in name only - with all state institutions still in the former capital Abidjan.

If President Gbagbo decides to stay on and fight, the battle for Abidjan is likely to be fierce. But before the main body of pro-Ouattara forces arrive, the city is already increasingly insecure and Mr Gbagbo's hold on power already looks shaky.