The Bolivian vice-president, Jorge Quiroga, on a visit to Washington, has called for increased aid from the United States to help combat coca production.

Mr Quiroga said that the authorities had managed to destroy three-quarters of Bolivia's illegal coca plantations in the last couple of years.

But he said that farmers were now being tempted by higher coca prices and he called on the US to provide assistance to prevent an increase in production.

Correspondents say that in recent years, Bolivia has made great strides in eradicating coca and encouraging farmers to plant alternative crops, although the leaves are still grown legally as a local stimulant.

From the newsroom of the BBC World Service