Two teenagers have been arrested on suspicion of drugs offences following the death of a 17-year-old youth at Leeds Festival.
The boy, from the Greater Manchester area, was taken to hospital at 4.45pm on Saturday after taking drugs, West Yorkshire Police said.
Two 17-year-old males were arrested in the Greater Manchester area on suspicion of drugs offences and are being questioned by police.
Police said they were contacted by staff at Leeds Festival after the youth was taken to St James' Hospital by ambulance in a critical condition.
A spokesman said he underwent emergency treatment but was pronounced dead shortly after midnight.
Chief Superintendent Keith Gilert, Leeds Festival's police commander, said: "Our thoughts are naturally with the family of the young man at this time.
"They were made aware of the incident by officers as soon as possible and were assisted to attend the hospital as quickly as possible. We will continue to support them through this difficult time.
"We are currently investigating the death and how he obtained the substance he took.
"Two males, aged 17, have been arrested in the Greater Manchester area on suspicion of drugs offences and are currently in custody.
"At this time the indications are that the man consumed drugs immediately before before he collapsed."
Mr Gilert warned festival-goers about the dangers of taking illegal drugs following the death of the teenager.
He said: "In partnership with the organisers, Festival Republic, we will continue to take action against those who risk the lives of others by supplying drugs.
"Anyone who has any concerns for either themselves or others at the festival should contact festival site or security staff or seek medical assistance."
One festival-goer said she believed she saw the teenager as he was being treated by medics.
Hayley Briggs said: "It was right outside the guest area and the guy just looked in a very bad way. He was ashen, head-to-toe grey, totally not with it at all.
"He was being cradled by one of the first aiders before the ambulance arrived. He looked as if he was going in and out of consciousness. Poor kid, it's really sad.
"There were a load of people around him just waiting for the ambulance to arrive and when it did the first aiders went straight out and they just got cracking."
Ms Briggs said she heard a number of people discussing drugs while she was at the festival and said one of her friends had been offered a number of different substances.