Ultra right-wing death squads in Colombia have killed at least 29 people over the weekend.

The BBC's Jeremy McDermott: "The warning to the area is clear"

The killers from the outlawed paramilitary army, the Self Defence Forces of Colombia, are targeting suspected rebel sympathisers as they continue a campaign against Marxist guerrillas in the Norte de Santander province.

Some 4,000 people have already fled in terror across the border to Venezuela.

No questions asked

The paramilitaries have a simple and effective strategy; they arrive in a town or village, seal it off, then with a list in hand, drag suspected guerrilla sympathisers into the street where they are executed.

The warning to the community is clear - those who support the rebels will be killed, no questions asked.

This latest campaign has already affected Venezuela, and the country's president, Hugo Chavez, has announced he will hold talks with Colombian Marxist guerrillas, with or without the permission of the Colombian government in an attempt to stop the spillover of Colombia's 35-year-old civil war into his country.

Authorities powerless

The border region with Venezuela has traditionally been a rebel stronghold, hence the President Chavez' wish to speak to those who hold the power in the area, and the paramilitary campaign to rid it of guerrillas.