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.

Farmers say the government’s coca eradication programme will destroy their livelihoods.

Asominuma said that “after several days of resistance on the part of peasant communities,” state forces opened fire on the protesting farmers.

The prosecutor’s office said several of the victims were shot in the head.

That contradicted Defence Ministry claims that a breakaway faction of Farc, the liberation army that has demobilised, attacked the demonstration with improvised mortar bombs and machine-gun fire.

A ministry statement said guerillas of the former Daniel Aldana front “threw at least five cylinder bombs at members of the security forces and at the crowd, and then attacked with indiscriminate fire from rifles and machine guns at demonstrators.”

But a statement from Asominuma denied that account, saying the allegations were concocted by “the army and the police in an attempt to justify excessive and irrational action,” which it branded “a clear violation of human rights.”

Asominuma said the massacre “shows us the true reality of the unmeasured force against the defenceless peasants who were peacefully demonstrating."

Community activist Jose Santacruz also said witnesses had told him Farc dissidents had no presence in the area and the security forces had opened fire on protesters.

Asominuma urged the government to guarantee development and welfare in the communities affected, saying: “The presence of the state cannot just be seen from the militarisation of the territories.”

And the Alto Negro and Frontera Negro Community Council demanded the Colombian government ensure the protection of leaders from both communities.

Farc has relaunched itself as a political party since signing a landmark peace deal with the government last year to end more than 50 years of civil war.

But assassinations of trade unionists and community leaders by right-wing paramilitary groups — supposedly disbanded several years ago — have continued unabated.