The remains, found in a cemetery in Puerto Berrio, in Antioquia department, were in "bags and buckets" and were at risk of "getting mixed up and prone to deterioration," a team official told AFP.

The team, known as the Search Unit for People Given Up as Disappeared (UBPD), was formed as a humanitarian government agency as part of the 2016 peace agreement with the FARC, the country's largest leftist guerrilla group.

They estimate that some 120,000 people have gone missing in the five decades of violent unrest in Colombia.

The investigators moved the remains to a safe location and will soon try to identify them, the official said.

"Among the bodies that were moved at least 104 showed lesions that could correspond to a violent death," team director Marina Monzon said in a statement.

Residents of riverside towns like Puerto Berrio in years past would pick up bodies found in the river and bury them as unidentified people.

Aside from the 416 bodies, "there are other bodies in the La Dolorosa cemetery in ossuaries and burial plots that may also be of missing people," the statement read.

Colombian forces continue to battle with a smaller rebel group, the ELN, as well as violent drug gangs and leftover paramilitary fighters.