Hooded gunmen killed three people in northwest Colombia, the latest attack in a two-week wave of violence that has left at least 42 people dead, police said Friday.

The killings occurred late Thursday near the town of Andes in Antioquia department when hooded men entered a farm and opened fire, regional police commander Colonel Ever Gomez said.

Two of the victims died instantly while the third succumbed in hospital.

"Among the victims is a 13 year-old minor," said Gomez.

He said the killers "opened fire without saying a word."

Violence has escalated in several parts of the South American country, leaving at least 42 people dead since August 11.

The government has accused armed groups financed by drug trafficking of being behind the killings. It is one of the biggest spikes of violence since the signing in 2016 of a peace agreement with leftist FARC guerrillas.

But the country, the world's biggest exporter of cocaine, still remains roiled by turf wars between competing armed groups, including dissident FARC members who rejected the peace deal as well as still-powerful Marxist ELN rebels.

A United Nations peace mission in Colombia, set up to monitor the peace agreement, condemned the violence in a statement on August 17, saying that so far this year it had documented 33 massacres -- defined as the murder of three or more people in a single act of killing.

Thursday's killing was the ninth in two weeks.

President Ivan Duque and Attorney General Francisco Barbosa on Friday jointly announced in Cali the arrest of two of the alleged perpetrators of one of the massacres, the August 11 killing of five black teenagers in a sugar cane field.

Barbosa said three people working as security guards in the area opened fire on the group as they entered their field to eat sugar cane.

Barbosa said the boys were murdered "in an act of total barbarism."

A third suspect is on the run, police said.