BOGOTA, Colombia (Reuters) -- Ultra-right gunmen tortured and killed at
                  least 12 people, including three pairs of brothers, in attacks that came after a
                  week of heavy fighting between Marxist rebels and the army, authorities said
                  on Thursday.

                  In the northwest town of San Carlos, paramilitary fighters dragged nine
                  people out of their homes on Wednesday night, officials said.

                  Their bullet-ridden bodies, with torture marks, were found dumped in a rural
                  area on Thursday.

                  The area is hotly disputed by the right-wing death squads and their guerrilla
                  enemies. The paramilitary gangs frequently target civilians they suspect of
                  collaborating with the rebels.

                  Three other men were killed in a separate attack near the town of Tulua in
                  southwest Valle del Cauca province on Thursday.

                  Earlier this year, ultra-right gangs said they were moving into the area to
                  combat a growing rebel presence there.

                  Colombian and international human rights groups accuse the military of tacit
                  backing and sometimes open support for the illegal paramilitary groups.

                  Despite some signs of progress in the slow-moving peace process between
                  rebels and the government, this week has seen some of the heaviest fighting
                  of the year.

                  Civilian authorities said guerrillas killed 45 Marines in the northwest town of
                  Jurado, near the Panama border on Sunday. The armed forces said they
                  have killed some 150 rebels in a counteroffensive since then.

                  More than 35,000 people, many of them civilians, have been killed in just
                  the last 10 years as a result of Colombia's long-running guerrilla war.

                     Copyright 1999 Reuters