Luis Diaz has spoken of his desperation and distress in an emotional call for the release of his father.
The Liverpool winger's parents were kidnapped at gunpoint in Colombia last week.
His mother has since been found, but his father remains missing.
The National Liberation Army (ELN), a left-wing guerrilla organisation, is behind the abduction.
Diaz made his appeal after coming off the bench to score a stoppage-time equaliser for the Reds in a 1-1 draw at Luton on Sunday.
The 26-year-old marked the goal by revealing a T-shirt bearing a message reading 'Freedom for Dad', and he followed that up with a post on Instagram.
It read: "Today the footballer is not speaking to you. Today Lucho Diaz, the son of Luis Manuel Diaz, is speaking to you.
"Mane, my dad, is a tireless worker, a pillar in the family and he has been kidnapped.
"I ask the ELN for the prompt release of my father, and I ask international organisations to work together for his freedom.
"Every second, every minute, our anguish grows. My mother, my brothers and I are desperate, distressed and without words to describe what we are feeling. This suffering will only end when we have him back home.
"I beg you to release him immediately, respecting his integrity and ending this painful wait as soon as possible.
"In the name of love and compassion, we ask that you reconsider your actions and allow us to recover him.
"I thank Colombians and the international community for the support received, thank you for so many demonstrations of affection and solidarity in this difficult time that many families in my country find themselves living."
Diaz's appearance as an 83rd-minute substitute at Kenilworth Road was his first since the kidnappings on October 28.
