Rightwing paramilitaries were believed to be holding ...
Rightwing paramilitaries were believed to be holding about 25 plantation workers hostage on Thursday after they released about 200 others following one of Colombia's biggest mass kidnappings.
The workers were seized on Tuesday evening as they returned on buses from a palm oil plantation in Casanare, a petroleum-rich department in eastern Colombia.
Humberto Caicedo, commander of local paramilitaries, claimed responsibility for the kidnapping in a statement and said it was carried out to counter left-wing guerrilla activity in the area.
Mr Caicedo walked free from Army custody last year, sparking an ongoing investigation of two colonels and a captain from the Army's 16th Brigade by the Colombian attorney generals office.
Robin Kirk, Colombia specialist at Human Rights Watch in Washington, said the kidnapping may have been intended as a display of strength after repeated threats by Mr Caicedo against the local population.
Colombia's paramilitary groups are outlawed but have been seeking a higher political profile in Colombia. The government has refused to treat them as a political grouping as it does with leftwing rebels.
The paramilitaries have grown from 4,500 members in 1998 to 8,150 last year, according to Colombia's defence ministry. Their increasing power is disturbing to many observers who believe the country's armed conflict is escalating and becoming more polarised.
Human rights groups believe paramilitarism is sponsored by the armed forces, and the government has been accused of failing to act sufficiently firmly against paramilitaries. Military commanders and the government admit some low and mid-ranking military officers may collaborate but say there is not state policy.
Arrests of paramilitaries have grown significantly according to government figures.
In many areas paramilitary control has become a defence against leftwing rebels. The paramilitaries derive much of their income from drug trafficking, and from protection money paid by the commercial sector in many communities.
Mass kidnappings have previously been a tactic of the ELN leftwing guerrilla group. Two years ago the group abducted around 150 worshippers from a church, and last month kidnapped 34 workers at an oil field operated by US oil firm Occidental.