Reports from Colombia say there has been an upsurge in rebel attacks just over a week before left-wing guerrillas are due to begin peace talks with the government.

Police said an officer was killed and three others injured when rebels from the Revolutionary Armed Forces of Colombia overran their barracks in the north-west of the country.

There's also been fighting between rebels and paramilitary groups, in which the leader of the biggest paramilitary force, Carlos Castano, is said to have been killed.

But the chief of the armed forces, General Fernando Tapias, has said there is no evidence that Mr Castano, who's wanted for peasant massacres and kidnappings, is dead.