Luis Diaz will decide for himself whether he can play for Liverpool in Sunday's English Premier League match at Luton Town following the kidnapping of his parents, manager Juergen Klopp said.

Diaz's mother, Cilenis Marulanda, and father, Luis Manuel Diaz, were taken by armed men as they were driving in La Guajira in northern Colombia on Saturday.

Marulanda was freed within hours and the kidnappers said on Thursday that his father would also be released.

"If he feels right, he will be will us. You can see he didn't sleep a lot," Klopp told a news conference on Friday.

"The news from Colombia gives us a little bit of hope. I cannot say what we will do. It's up to him, if he makes himself available or not."

Colombia's government reported the ELN was responsible for the kidnapping.

Interior minister Luis Fernando Velasco said the situation was "very serious" and that it violated a ceasefire between the government and the rebels.

Earlier on Thursday, the government's peace delegation charged with negotiating with the ELN called for Diaz's father to be released immediately. Diaz's father will be released "as soon as possible," ELN representative Juan Carlos Cuellar told a community meeting.

Peace talks between the ELN and the government restarted last year in hopes of ending the group's part in Colombia's 60-year conflict.