Colombia's two main cocaine cartels have resumed their bloody war with a series of tit-for-tat kidnappings and murders, police said Friday.

Twelve men were kidnapped Thursday from a slum hotel in Medellin, Colombia's second-largest city, and within hours two were found murdered and a third was wounded, according to a national police report.All the men were residents of Cali, home base to a cocaine cartel that competes with the Medellin clan for access to the lucrative U.S. drug market.

Police said the two murdered men had long criminal records.