Two people died, another dozen were taken to hospital, and hundreds of others sought medical help for a suspected overdose at a Sydney music festival, police said.
A 23-year-old man and a 21-year-old woman died on Saturday after collapsing at the Defqon.1 festival, police said.
Two of the 13 hospitalized persons are still in critical condition, while about 700 were seeking help on the ground.
The police have indicted ten people for drug-related offenses, including two adolescents allegedly bringing 120 capsules to the festival at the Sydney International Regatta Center.
"I'm absolutely horrified by what happened, I do not want any family going through the tragedy that some families are experiencing this morning, it's just terrible to think about it," said Gladys, the premier of the Australian state of New South Wales Berejiklian, said.
"This is an unsafe event and I will do my utmost to ensure it never happens again," she added.
Ms. Berejuklian denied that the cancellation of the event would force him and others to go underground and said that pill-testing at music events was "not a solution."
"Those who support pill-testing give the go-ahead for drugs, there is no safe drug, and unfortunately, when young people think this is the case, it has tragic consequences," she said.
In 2013 and 2015, two men died in their 20s during the festival, both from a suspected overdose of drugs.
The festival, which has been held annually in Australia since 2009, was organized by Q-Dance Australia as part of the Dutch event
On Sunday, the organizers said they were "deeply saddened by the deaths."
"We are disappointed with the number of reported drug-related incidents, we have a zero-tolerance policy on drug use at the festival," said Defqon.1 in a statement by the Sydney Morning Herald.
At the festival in the Sydney International Regatta Center, a total of 69 people were found drugged.
Local detectives have formed a new police force called Highworth to investigate the two deaths.
About 30,000 revelers participated in this year's event.
Allan Sicard, Deputy Commissioner for Police in New South Wales, said the police have done everything in their power to ensure the security of the event.
"What we can not do is to be in people's minds, to be in people's decision making when they decide to use illegal drugs," he said.
"The police can only do so much."
He said it was too early to determine if the same drug was responsible for the deaths and hospitalization.
He added, however, that toxicology testing would be accelerated and completed within the week.
A spokesman for Defqon.1 organizers said they were "deeply saddened by the couple's tragic death" and sent condolences to their families.
"We are disappointed with the number of reported drug-related incidents, and we have a zero-tolerance policy on drug use at the festival.
"The organizers of the festival work closely with the authorities to cooperate with the authorities on deaths and the number of medical presentations made during the evening, and a comprehensive investigation is underway.
"Because it's the NSW police and the medical examiner and out of respect for the families and friends, we will not speculate on the cause of death."