The Democratic Coalition, which groups trade unions, student groups, and associations of blacks, peasants and indigenous people, called the nationwide protests, which began on Wednesday and continued Thursday and Friday.
Activists and human rights groups denounced threats and abuses by military and paramilitary groups.
The organisers said Thursday that seven protesters were injured when the police tried to break up the demonstrations, and the press reported Friday that a total of 15 people were wounded.
The organisers also reported the arrest of community leader Isaac López, who was accused of ties to the Revolutionary Armed Forces of Colombia (FARC), the main rebel group involved in Colombia’s decades-long armed conflict.
López, the leftwing Alternative Democratic Pole candidate for mayor in the town of Cartagena del Chairá in the southern department (province) of Caquetá, was arrested Wednesday on his way to the local protest, said the organisers.
In September, leaflets were circulated by the army urging people not to take part in the planned protests: "Do not participate in acts of terrorism. Do not let them continue to use you as cannon fodder. Do not go to the FARC demonstration. Do not be an accomplice to terrorists and murderers."
Agriculture Minister Andrés Felipe Arias accused the demonstrators of links to the FARC.
"That claim is aimed at diverting attention from the real aims of the national campesino (peasant farmer) mobilisation," Diana Nocua, one of the organisers of the nationwide demonstrations, told IPS. "We are independent, and we are defending the rights of the victims of persecution and anti-democratic measures."
The demonstrators protested the free trade agreement negotiated with the United States, the privatisation of water utilities and the health and education systems, the current labour legislation, and incentives offered to foreign companies and investors, which they described as "a disgraceful giveaway of national sovereignty."
They also took aim at cuts in funding for health and education in rural areas, demanded the repeal of the government’s "national development plan", land laws and mining code, and called for the cancellation of concessions granted to foreign extractive companies since Uribe became president in 2002.
In addition, the Democratic Coalition called the demobilisation of the ultra-rightwing paramilitary United Self-Defence Forces of Colombia (AUC) a "farce" and demanded respect for the collective land rights of black and indigenous communities.
In response, Minister Arias told the media that in the southwestern department of Cauca, 12,000 hectares of land have been distributed to indigenous communities.
But the Cauca Regional Indigenous Council (CRIC) replied in a communiqué that land assigned to 12 displaced families formed part of an indigenous reserve and had been claimed by the Kokonuko native community for more than 25 years.
Arias, meanwhile, said three more purchases of land for rural families had been suspended until the demonstrations came to a halt, and warned that the protesters would not be allowed to block roads "because the security forces will enforce respect for public spaces."
The organisers of the protests issued a communiqué with the names of seven people -- one woman, five men and one minor -- who were injured.
"Civilians who gathered peacefully in Mondomo, Cauca, were attacked by the military police and counterinsurgency forces, who sprayed tear gas and ground glass, used explosives and fired shots," said the statement.
Similar crackdowns by the police and anti-riot police (ESMAD) were reported in areas near Cali, in the western department of Valle del Cauca, which affected children and elderly persons, and led to the arrests of 11 people.
In the central department of Huila, two military trucks parked across a highway blocked 1,200 campesinos from marching to the provincial capital, Neiva. According to the Rural Press Agency, Jorge Garzón said the campesinos were organised and ready to join the demonstration in the city, "but they are not letting us pass."
And in Ibagué, the capital of the central department of Tolima, some 4,000 campesinos gathered in parks and public spaces around city hall. "They came in on Tuesday from different municipalities where they face serious persecution and arrest. But their health conditions are beginning to worry us," said Diana Nocua.
There have been similar demonstrations and complaints of harsh police action in most of Colombia’s regions over the past three days.
The "Black Eagles", the largest paramilitary group made up of "demobilised" members of the AUC, which took part in a high-profile but controversial demobilisation process, were reportedly involved in some of the violent incidents.
The precedent for the current nationwide demonstrations dates back to 1996, when coca growers protested the start of aerial spraying of their crops in the southern departments of Caquetá, Putumayo and Guaviare.
At the time, the farmers stressed that they did not grow coca out of choice, or under pressure from the guerrillas, but because they had no other way to earn an income.
Over time, the campesino mobilisation expanded to other regions, where the demonstrators have traditionally been the target of harsh crackdowns.
"We have suffered 30 arbitrary arrests in the last two months" in the municipalities of Tolima, Cauca and Santander, Aydeé Moreno, another of the organisers, told IPS.
One case occurred on Sept. 29, when state security agents raided the offices of the Campesino Association of the Valle del Río Cimitarra (ACVC) in the northeastern city of Barrancabermeja, and arrested four of the group’s members.
And on Oct. 5, in the town of Yondó in Antioquia in the northwest, army troops tore down posters publicising the coming protests and warned local residents, according to the ACVC, that they would "burn down houses if they found new posters, because the order is to not allow the protest to be held in the region."
The same day, in Planadas in the west-central department of Tolima, campesino leader Hernando Soto was arrested by the army. Three days later, in the town of Rioblanco in the same department, two young men were seized by an infantry battalion.
The Committee of Solidarity with Political Prisoners (CSPP) said that on Tuesday a bus was blocked from carrying food supplies for the demonstrators from the town of Rovira to Playarrica, and troops stopped another bus in Chaparral (in Tolima) that was carrying campesinos.
The organisations denounced that campesinos were seized and "disappeared", and that others were murdered. The victims were later accused of belonging to leftist insurgent groups, especially the FARC.
* With additional reporting by Constanza Vieira. (END/2007)