Organisers of a party at an amusement park in Taiwan have been detained for questioning after a fire tore through crowds at a party.
The number of people injured has been confirmed at 498, as authorities begin an investigation into the cause. A coloured powder apparently ignited after being discharged from the stage onto the audience.
Footage showed people panicking and screaming, and inflatable water toys used as stretchers.
Some 182 injured are in intensive care.
Officials said many of the victims appear to in their 20s or younger.
Some of them breathed in the powder, causing respiratory problems.
The water park outside the capital Taipei has been closed, and so-called colour parties have been banned while the investigation into what caused the inferno proceeds.
Event manager Lu Chung-chi and several staff members were detained by police and are being questioned by prosecutors.
Mr Lu was pictured in the Taiwan News with handcuffs on and his hands in a prayer position. The news site said he had apologised for what had happened and pledged to take responsibility for it.
Footage of the incident shows a party in full swing when fire suddenly erupts.
It was "hell", a male student who sustained minor injuries said, according to AFP news agency.
"There was blood everywhere, including in the pool where lots of the injured were soaking themselves for relief from the pain."
His girlfriend added: "I saw lots of people whose skin was gone."
The fire was quickly brought under control.
The fire department said the powder, used to create a party atmosphere, may have ignited due to the heat of the lights on the stage, or from sparks from machinery.
The substance is also used in other countries. It is made of dried corn and can be highly flammable, said the BBC's Taipei correspondent.
The 519 victims were sent to 41 hospitals, and 413 are still in hospital, say municipal authorities.
The incident occurred about 20:30 on Saturday. More than 1,000 people were near the stage at the time.
Many people flocked to water parks on Saturday as temperatures reached 36.6C in Taipei and as high as 38C in other parts of Taiwan.
Taiwan has suffered a series of deadly fires in the past couple of years due partly to poor enforcement of building and fire safety codes and illegal construction, our correspondent says.
A fire earlier this year killed six firefighters, prompting orders to rectify illegally constructed buildings and upgrade firefighters' equipment and training.