At least nine people have been shot to death outside Medellin in Colombia's countryside in a massacre police suspect, is a settling of accounts between drug traffickers.

Five men and four women were killed on a farm, apparently in the early morning hours of Monday and none were identified, Yesid Vasquez, commander of the Metropolitan Police Department in Medellin, said.

Vasquez said victims appeared to be celebrating in a rented villa in Envigado, near Medellin - Colombia's second largest city - when they were shot.

The victims were apparently shot with guns that had silencers, explaining why no one nearby reported hearing gunfire, he said.

Santiago Londono, secretary of government for Antioquia department, said one woman survived the massacre and is being questioned by investigators.

Source: Agencies