A suspected paramilitary successor group killed 10 farmworkers at a rural property in the northwestern Colombian province of Antioquia, police said.

The crime was committed by a group of armed men in a rural area of Santa Rosa de Osos, a town north of the city of Medellin, a National Police spokesperson said.

One farmworker was wounded but survived the Wednesday evening massacre at the La España tamarillo farm, the spokesperson said, adding that the Los Rastrojos criminal gang is suspected of carrying out the killings.

The Los Rastrojos gang is one of several heavily armed drug-trafficking gangs that emerged following the ostensible demobilization of the AUC militia federation in 2006.

The spokesperson said the regional National Police commander, Col. Jose Gerardo Acevedo, traveled Wednesday night to the massacre site to coordinate efforts to track down the assailants.

Antioquia Gov. Sergio Fajardo told Caracol Radio that the initial hypothesis is that the workers were killed after the owner refused to pay protection money.

A report from the Indepaz think tank released in February said the paramilitary successor groups Los Rastrojos, Los Urabeños, Las Aguilas Negras, Los Paisas and ERPAC had a presence last year in 406 municipalities in 31 Colombian provinces.

That means their presence expanded by 147 municipalities compared to 2008, when they were active in 259 of the Andean nation's 1,110 municipalities.

Los Rastrojos have a presence in 23 provinces, Los Urabeños in 18, Las Aguilas Negras in 23, Los Paisas in 14 and ERPAC in 14, according to the study.

More than 31,000 AUC fighters laid down their arms between the end of 2003 and mid-2006 as part of a peace process with former President Alvaro Uribe's administration.

The AUC, which arose in the mid-1980s to protect landowners and businesses from Marxist rebels but degenerated into a fractious coalition of death squads whose chiefs grew rich from drug trafficking, land grabs and extortion, has been linked to more than 20,000 murders. EFE