The rebel group holding Luis Diaz's father claim military action is delaying the release of their hostage and putting him at risk.

Diaz's parents were kidnapped over a week ago — his mother was subsequently freed quickly — and despite pledges from the National Liberation Army of Colombia to expedite the return of Diaz Sr, it is taking longer than expected. 

A statement, signed by unit leader Commander Jose Manuel Martinez Quiroz, read: "On November 2, we informed the country of the decision to release Mr Luis Manuel Diaz, father of the player Luis Diaz.

"From that date, we began the process to accomplish this as soon as possible. We are making efforts to avoid incidents with government forces. 

"The area is still militarised, they are carrying out flyovers, disembarking troops, broadcasting and offering rewards as part of an intense search operation. 

"This situation is not allowing for the execution of the release plan quickly and safely, where Mr Luis Manuel Diaz is not at risk. 

"If operations continue in the area, they will delay the release and increase the risks. 

"We understand the anguish of the Diaz-Marulanda family, to whom we say that we will keep our word to release him unilaterally, as soon as we have security guarantees for the development of the liberation operation."

Diaz came off the bench to score a late equaliser for Liverpool at Luton on Sunday before lifting his shirt to display the message "Libertad para Papa" (Freedom for dad). 

The winger, who was making his first appearance since the kidnappings, later posted an emotional message on Instagram calling for his father's release.