The top commander of Colombia's left-wing FARC rebel group has been killed in a military operation.

The Colombian President Juan Manuel Santos confirmed on Saturday morning that Alfonso Cano had died in the mountains in Cauca, in the south-west of the country, the BBC reported.

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In a national television address, Santos described the death of Cano, whose real name is Guillermo Saenz Vargas, as “the biggest blow against the FARC in all its history”.

"I want to send a message to each and every member of that organization: demobilize ... or otherwise you will end up in a prison or in a tomb. We will achieve peace."

FARC, the Revolutionary Armed Forces of Colombia, is on US and European terrorist lists, and is reportedly the oldest and largest of Colombia's left-wing rebel groups.

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Cano was shot dead in a fire fight with security forces during an operation in which the military bombed his position in the town of Suarez, the Washington Post reported.

Pictures of Cano, 63, minus his trademark beard, were later broadcast on Colombian television.

However the death of Cano does not mean the end of the FARC, which still has an estimated 9,000 fighters.

