Among the dead was Freiman Velasquez, a leader of a local farmers' rights organization. The group was traveling with personnel from a unit that protects people who face threats.
Among the dead were bodyguards tasked with protecting Velasquez.
Colombia has recently been shaken by one of the worst waves of violence since the historic peace agreement between the Colombian state and the now-defunct FARC guerrilla group was signed in 2016.
The campaign ahead of the May 31 election, when the successor to leftist President Gustavo Petro will be elected, has been marked by several attacks.
