The paramilitary block - part of a nationwide force - is waging an illegal war against leftist insurgents in Medellin, Colombia's second-largest city, and throughout Antioquia province. Three soldiers were wounded in the fighting. The offensive may help ease concerns that the U.S.-backed military under the new president would give free rein to the paramilitaries. Human rights monitors have frequently criticized the military for collaborating with paramilitary forces, which last year were responsible for most of the massacres committed in Colombia. Uribe - a former Antioquia governor - also has been dogged by charges that he's tied to the paramilitaries.***