The fire happened during a party in the building
The family of a talented young Irish jockey has said he was one of two people who died in an arson attack at a block of flats in England.
18-year-old Jamie Kyne was originally from County Galway where his family ran the Kiltrogue stud farm.
He was killed alongside a young woman, who is also believed to have been an apprentice jockey.
A man has been arrested over the incident which happened during a party in Norton, near Malton in Yorkshire.
Mr Kyne's aunt said: "The family are devastated and Jamie was a star."
'Devastated and shocked'
The mother of jockey Jan Wilson, 19, said she was waiting for confirmation her daughter was the other victim.
Two men were also taken to hospital and treated for minor burns and the effects of smoke inhalation.
Twenty-year-old apprentice jockey Ian Brennan, who is also believed to be Irish, jumped to safety from the third floor of the building.
Born in Co Galway, Ireland
Rode first winner in 2007
Rode to 29 victories in 2009
Dubbed "the apprentice find of the season"
He has since been released from hospital.
The injuries of the other man are not thought to be life-threatening, police said.
Mr Kyne's aunt said of his parents: "They are so proud of him. At the moment they are just devastated and shocked."
Mr Kyne had been due to ride at Haydock on Saturday.
He was lying third in the apprentice jockeys championship, having had 29 winners in the year so far.
Hundreds of people have already joined a Facebook page, leaving tributes to the popular young jockey.
Horse trainer Adrian McGuinness, from Lusk, County Dublin, said: "He was very good, one of the best young riders about and probably one of the top apprentices in England at the moment.
"They called him the jewel of the north."
The bodies of the victims remained in the building as emergency services worked to make it safe to enter.
Stuart Simpson, of North Yorkshire Fire Service, said crews had arrived at the scene within five minutes but were prevented from accessing the house immediately by a fire on the staircase.
About 60 firefighters tackled the fire at the large red brick building, which is known as the Tannery and used as accommodation for apprentice jockeys.
Thirsk and Kempton racecourses have observed a period of silence as a mark of respect to the victims.
Jockeys at Stratford were wearing black armbands in tribute and York racecourse was flying its flags at half-mast.
Racehorse trainer John Quinn, who runs stables at Malton, was on his way to the scene of the fire to speak to investigating officers.
"It's awful. I am just hoping we'll know something soon.
"It's just a nightmare", he said.
Eyewitnesses said survivors were thought to have jumped out of windows to flee the fire, which started at about 0215 BST on Saturday.
Catherine Hyder, who lives opposite the flats, said: "My husband heard a girl come down onto the street and was banging on doors to raise the alarm.
"She said someone had jumped out of one of the windows. We could see the flames at the back and there were a lot of fire brigade people around."
"It was scary and quite noisy."
The landlord of a nearby pub, Steve Kinsella, described the girl in the street.
"I just heard someone shouting. So I looking through the window and saw a girl just running in the street," he said.
"All she had on was a T-shirt. She was shouting 'Fire, fire', screaming at the top of her voice."
Local councillor Howard Keal, who lives near the scene, said he had spoken to many people in Norton who are devastated by what had happened.
He said: "There is a profound sense of shock that something terrible has happened today in this community."