Luis Díaz made an extraordinary return for Liverpool as he scored a 95th-minute equaliser as his team drew 1-1 with Luton Town in the Premier League on Sunday while awaiting the promised release of his kidnapped father by Colombia's National Liberation Army (ELN) guerrillas.

After scoring his late goal, Díaz lifted his Liverpool shirt to reveal a message underneath that said: "Libertad para papá" (Freedom for dad).

The Colombia international had missed Liverpool's past two matches after his mother, Cilenis Marulanda, and father, Luis Manuel Díaz, were seized by armed men in northern Colombia. His mother was freed within hours and the ELN guerrillas said on Thursday that they would free his father.

The 26-year-old was brought on by manager Jurgen Klopp as Liverpool searched for a way back into the game against Premier League strugglers Luton, who had gone ahead shortly before Díaz's introduction thanks to a goal from Tahith Chong.

However, just as it seemed as though Liverpool would come away with nothing from a match that they had dominated for the most part, Díaz leaped highest at the back post to meet Harvey Elliott's cross to head the ball beyond Luton goalkeeper Thomas Kaminski.

"A wonderful moment but it doesn't change the situation. Most important thing is that his father gets released," said Klopp after the game. "It is wonderful he wanted to be here. For us a super important goal and for him very important and emotional, but that's it.

"We knew he would be a threat. We didn't know how long he would play because he only had a few sessions with the team. But that is not the most important part today. He scored the goal but we need to see some improvement in Colombia."

Colombia's government said on Thursday that the ELN was responsible for the weekend kidnapping of the forward.

Díaz'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 group with Reuters.

"It says a lot about his character, about his inner strength," Diaz's teammate Alisson said after the match. "Not a lot of people can imagine what he is going through. Football can bring joy in dark moments."

The peace delegation of the Colombian government, which is in negotiations with ELN, said in a statement earlier Thursday that it was "officially aware" that the kidnapping had been "perpetrated by a unit that belongs to ELN."

"We demand that the ELN releases immediately Mr. Luis Manuel Díaz and we say as of now that they are entirely responsible to secure his life and integrity," said Otty Patiño, who leads the peace delegation.