Colombian law enforcement, they said in a joint declaration, "continue committing serious and widespread human rights violations" two months into a popular protest movement against the government.
The document was issued in the name of hundreds of rights groups in Colombia and around the world.
It denounced dozens of killings by police and armed civilians acting "with the complicity of law enforcement officials," as well as more than 3,000 arbitrary detentions of protesters -- many of them subjected to torture and other ill-treatment.
The groups said eighty people have suffered eye injuries, and 114 gunshot wounds.
"Of particular concern is the practice of enforced disappearance, with detained people transferred to unauthorized places of detention, such as shopping malls, schools, and public transport stations, and held incommunicado for up to 36 hours," said the document.
"To date, 327 people are still unaccounted for."
Colombia has been rocked by protests since April, following opposition to a proposed tax hike that morphed into a mass movement against the right-wing administration of President Ivan Duque.
The demonstrators demand an end to police repression and more supportive public policies to alleviate the economic impact of the Covid-19 pandemic, which has plunged more than 40 percent of the country's 50 million inhabitants into poverty.
The international community has condemned the security response that has left more than 60 people dead, according to the country's ombudsman.
The government claims that illegal groups involved in drug trafficking and the National Liberation Army (ELN) -- Colombia's last recognized guerrilla group -- have infiltrated the protest movement in a bid to sow chaos.
A major group representing the protesters said on June 16 it would suspend demonstrations, promising to "continue our struggle in other settings such as art and concerts".
More hardline factions in the movement have pledged to carry on.
