Castano is notorious throughout Colombia

Unidentified attackers opened fire on Carlos Castano on Friday, killing several bodyguards, but the leader escaped and has not been seen since.

The attack came as the AUC was in talks with the government to demobilise its 13,000 heavily armed fighters.

Castano has been convicted of innumerable massacres and murders and is one of Colombia's most feared men.

Indications are that the attempt was carried out by other right-wing paramilitaries linked to the drugs trade, the BBC's Jeremy McDermott reports.

It seems that elements within the AUC (United Self-Defence Forces of Colombia) feared Castano was about to cut a deal with the US, where he is wanted on charges of smuggling 17 tonnes of cocaine.

His wife, Kenia Gomez, has asked the authorities for protection after the attack on Castano's ranch.

Drug traffickers

Castano founded the AUC in 1997 although he had been fighting a war to the death with the country's left-wing rebels ever since they kidnapped and killed his father over 20 years ago.

Since then, the paramilitaries have become little more than armed drug traffickers.

Castano called a unilateral ceasefire in December 2002 and started a peace process with the government.

However, he has long lost control of the movement he founded and it seems several paramilitary factions want him dead, fearful of what he will tell the authorities should he cut a deal.