COLOMBIAN police have killed nine coca leaf-growers protesting against an eradication sweep, farmers said on Thursday.

The Association of Community Action Boards (Asominuma) said another 18 were injured in clashes with state police on Wednesday near Tumaco in the south-western coastal state of Narino, Latin American news site TeleSur reported.

The clashes occurred as hundreds of farmers formed a human chain to prevent the entry of crop-destroying teams in the Alto Mira and Frontera areas of Llorente Corregimiento in Tumaco municipality.