They died in inter-communal violence in one district of the city, it added.

The head of the ICRC delegation in the country said the event was particularly shocking in its scale and brutality.

Fighting has continued in Abidjan between forces loyal to the UN-recognised president Alassane Ouattara and the incumbent, Laurent Gbagbo.

Mr Ouattara was internationally recognised as president last year after the electoral commission declared him the winner of a November run-off vote, but Mr Gbagbo also claimed victory and refused to leave office.

The ICRC said delegates and volunteers from the Ivorian Red Cross visited Duekoue on March 31 to gather evidence of the killings, which are believed to have taken place on March 29.

The Geneva-based organisation said tens of thousands of women, men and children had fled the fighting in Duekoue since March 28.

The International Organisation for Migration (IOM) said many Duekoue residents were heading to the nearby town of Guiglo "fearing for their lives".