A representative of Colombia's National Liberation Army rebels says the group will free the father of Liverpool football star Luis Diaz "as soon as possible".
Diaz's father will be released "as soon as possible," ELN representative Juan Carlos Cuellar told a community meeting, in a video clip shared by the ELN with Reuters.
The striker's mother Cilenis Marulanda and father Luis Manuel Diaz were taken by armed men as they were driving in La Guajira province on Saturday. Marulanda was freed within hours.
The incident threatened ongoing peace talks between the ELN and the government, which restarted last year in hopes of ending the group's part in the country's 60-year conflict, which has killed at least 450,000 people.
The government and the ELN began a six-month ceasefire in August as part of talks.
Interior Minister Luis Fernando Velasco said earlier the kidnap situation was "very serious."
"This is a violation of the ceasefire and, of course it puts the process at risk," Velasco told journalists.
"We remind the ELN that kidnapping is criminal, violates international humanitarian law and that its duty in building the peace process is not just to stop kidnapping but to eliminate it forever," Otty Patino, head of the government's peace delegation, said in the statement.
He had called for Diaz's father to be freed immediately.
Marulanda and her husband Luis Manuel Diaz were kidnapped by armed men but while the footballer's mother had been released his father was held.
The ELN, Colombia's most radical leftist guerrilla group, has long funded its operations with kidnapping, as well as extortion and drug trafficking, according to security sources.