BOGOTA (Reuters) -- Marxist rebels stormed two towns and attacked key
                  highways in western Colombia, killing at least 11 people and wounding 30
                  others, including civilians and security force members, authorities said on
                  Tuesday.

                  The raids came as President Andres Pastrana scrambled to break the
                  deadlock in planned talks to end the South American nation's long-running
                  civil conflict and called on the guerrillas to "demonstrate their will for peace."

                  The worst attack, which began shortly after nightfall on Monday and lasted
                  until dawn on Tuesday, was in San Francisco in northwest Antioquia
                  province.

                  A joint force of Revolutionary Armed Forces of Colombia (FARC) and
                  National Liberation Army (ELN) rebels fired rockets and grenades at the
                  police post and nearby houses, killing one police officer and seven civilians.
                  Five police officers and 10 civilians were injured by flying shrapnel and
                  debris, a police spokesman said.

                  In a simultaneous strike on the nearby town of Cocorna, also in Antioquia
                  province, ELN and FARC fighters killed three soldiers and destroyed a
                  temporary police barracks. Two police officers were wounded and seven
                  civilians were hurt.

                  As they retreated into the surrounding hills, the guerrillas blew up a bridge on
                  the freeway that links Bogota with the regional capital, Medellin, paralyzing
                  traffic.

                  In a separate incident on Monday, FARC rebels ambushed a patrol of
                  counterinsurgency troops on the Pan-American highway where it snakes
                  down into southwest Cauca province. At least six soldiers were wounded,
                  army sources said.

                  Elsewhere, insurgents torched seven buses near the town of Yarumal on a
                  road that links Antioquia with the Caribbean coast.

                  The FARC and the ELN, the oldest and largest rebel forces in the
                  hemisphere, have said they are ready to negotiate an end to their
                  30-year-old uprising that has killed more than 35,000 people in the past 10
                  years alone.

                  In an effort to jump-start talks with the FARC, Pastrana pulled some 2,000
                  troops out of an area the size of Switzerland in the southeast at the start of
                  last month.

                  But rebel chieftains have blocked the start of formal negotiations until the last
                  100 soldiers are withdrawn from barracks in San Vicente del Caguan, the
                  largest town of the 16,000-square-mile (42,000-sq-km) demilitarized zone.

                  In comments to local media on Tuesday, Pastrana hinted he may cede to
                  those demands, while calling on the guerrillas to moderate their stance.

                  "The government is willing to do everything necessary within the bounds of
                  the law and the constitution to get the peace process under way," he said.
                  "But Colombians want gestures and actions of peace that show the
                  insurgents will sit down at the negotiating table as soon as possible."

                  But in a video apparently released by guerrilla sympathizers in San Vicente,
                  rebel commander Jorge Briceno, No. 2 in the FARC, threatened to step up
                  attacks on at least six towns just outside the demilitarized zone. It was not
                  immediately clear when the video was recorded.

                   Copyright 1998 Reuters.