Rightwing death squads have threatened to kill members of an international human rights group which includes British volunteers working in some of the most dangerous regions of Colombia.
Paramilitary gunmen have warned members of Peace Brigades International (PBI) that they are now considered a "military objective" because of their work with community groups in the northern town of Barrancabermeja.
PBI teams - which include British, Canadian and Australian volunteers - provide unarmed escorts for community activists, trade unionists and human rights workers who are often targets of the rightwing militias.
Two gunmen burst into the offices of the Popular Women's Organisation (OFP), a local women's group, during a peace demonstration on Wednesday.
Identifying themselves as members of Colombia's largest paramilitary group, the United Self-defence Force of Colombia (AUC), they confiscated mobile phones and a passport belonging to a Swedish PBI volunteer. "From this moment onwards, you are targets," they warned.
OFP runs soup kitchens for war refugees in Barrancabermeja, an industrial town of 200,000 people which has become a battleground for the warring factions.
Once a stronghold of leftwing rebels, the town is now dominated by the paramilitary squads. Guerrillas and paramilitaries rarely confront each other directly, and most of their victims are unarmed civilians accused of collaborating with the other side.
Last year the bloody conflict claimed more than 500 lives in Barrancabermeja. Human rights monitors say most killings are the work of the paramilitaries. "We know that when they make a threat they're not playing around," said Yolanda Becerra, an OFP organiser.
OFP organisers say that they have been targeted for denouncing paramilitary abuses. "They are recruiting boys as young as 12 ... they seduce them with £150, a cellphone and a gun. As women and mothers, we cannot allow this," said Ms Becerra.
"The paramilitaries don't understand that a women's group can have an independent political position. They say that we're a front organisation for the insurgents," she said.
Since the early 1980s PBI has accompanied endangered activists like Ms Becerra in countries around the world. Volunteers have been harassed, mortar-bombed and stabbed, but they are believed to have saved scores of lives.
"We're unarmed, so in terms of protection we depend on the support of the community behind us," said a PBI spokeswoman, Emma Eastwood.
In Barrancabermeja, nine volunteers provide 24-hour accompaniment for the OFP and other local groups.
"The organisations we accompany have been threatened very seriously over the years and are now threatened on a daily basis," said Denise Cauchi, 33, a former journalist and one of four British PBI volunteers in Colombia.
"I wouldn't say you ever get used to [the danger], but there's no time to get carried away by your emotions. There's only time to focus on what you have to do."
Wednesday's death threat came as President Andres Pastrana met the leader of Colombia's largest rebel group in what many saw as a last-ditch attempt to save the country from all-out war.
He travelled to the heart of guerrilla-controlled territory for a two-day meeting with Manuel "Sureshot" Marulanda, commander of the 17,000-strong Revolutionary Armed Forces of Colombia (Farc).
The militias have grown rapidly in recent years, now fielding some 8,000 fighters, and despite government denials, human rights groups say that the militias still receive support from some police and army officers.
Farc has refused to make any concessions or declare a ceasefire. Rebels continue to kidnap civilians and attack villages, even though the government has withdrawn police and troops from an area twice the size of Wales, a condition for negotiations.
Colombians have steadily lost faith in the talks, which have failed to bear fruit and many are calling for a tougher stance against the guerrillas.
"There is an incredibly polarised conflict in Colombia. They're in a situation which could almost be described as a civil war, and in that kind of situation, the civilian population and organisations which defend it tend to get caught up in the crossfire," said Ms Eastwood.
© Guardian Newspapers Limited 2001