BOGOTA, Colombia (AP) — Thousands of Colombians dressed in white are flooding into the streets to repudiate terrorism after a car bombing at a Bogota police academy killed 21 people and left dozens more wounded.

President Ivan Duque is leading the march in the capital that is expected to conclude in the emblematic Plaza Bolivar.

The attack was the country’s deadliest in 15 years and recalled some of the bloodiest chapters in Colombia’s recent past.

Authorities have attributed the bombing to the National Liberation Army — the last major guerrilla group following a 2016 peace deal with the Revolutionary Armed Forces of Colombia.

Duque has asked Cuba to arrest 10 rebel commanders who had been living on the communist-governed island with his permission in a fading attempt to jumpstart stalled peace talks.