Colombia’s police on Sunday opened fire and used teargas against international observers investigating a massacre allegedly carried out by an anti-narcotics unit a few days earlier.

The commission existing of Colombian and international officials, journalists and members of non-governmental organizations came under fire after traveling to the municipality of Tumaco in Nariño to investigate possibly one of the deadliest massacres in 15 years.

At least six and possibly as many as 15 civilians were killed on Thursday when an anti-narcotics police unit allegedly opened fire on protesting coca farmers.

Organizations that took part in the mission

United Nations

Organization of American States

Nariño Governor’s Office

Ombudsman’s Office

Semana

El Espectador

Pacifista

Marcha Patriotica

Justicia y Paz

The ombudsman’s office had undertaken the mission to verify claims that police would have massacred as many as 15 unarmed protesters on Thursday.

According to local media, one member of the humanitarian commission trying to investigate the massacre was injured in the shooting.

#URGENTE Misión Humanitaria de organizaciones nacionales e internacionales fueron atacadas con tiros al aire cuando se dirigían hacia el punto donde ocurrió la masacre en Tumaco, entre las personas que acompañaban la misión habían periodistas, mapp OEA y Diócesis de #Tumaco Programa Somos Defensores Contagio Radio Posted by Marcha Patriótica Nariño on Sunday, October 8, 2017

According to weekly Semana, whose journalist witnessed the shooting, the policemen had ordered the group to “go away” after which the observers informed the police they were authorized to travel through the coca-rich region.

Immediately after, the policemen threw teargas and shot stun guns. Members of the commission fled into the forest after which they seemingly continued to be shot at, also by regular rifles, in spite of regularly identifying themselves as civilians.

Policía dispara a comisión de verificación en Tumaco #TUMACO | Reporteros de ¡PACIFISTA! acompañaban a la comisión que verificaba este domingo la masacre en Tumaco, cuando la Policía disparó. #NiUnMuertoMás #ProyectoCOCA Posted by PACIFISTA on Sunday, October 8, 2017

The aggression targeting officials and civilians has further embarrassed the National Police that has sustained Thursday’s massacre was initiated by dissident FARC guerrillas.

These claims were immediately denied by locals and human rights organizations that claimed members of an anti-narcotics unit opened fire at protesting coca farmers.

The UN and government officials who were shot at were wearing clothing that made them easily recognizable.

Vice-President Oscar Naranjo confirmed the policemen acted outside the law.

The police’s anti-narcotics director Jose Angel Mendoza said that “of course the Police regrets this type of situation. We apologize to the commission members.”

Mendoza denied the policemen had used deadly force, which was rejected by the journalists who published videos of the shooting.