RIO DE JANEIRO (AP) — A 23-year-old Taylor Swift fan died at the singer’s Eras Tour concert in Rio de Janeiro Friday night, according to a statement from the show’s organisers in Brazil. Both fans and politicians reacted to the news with outrage.

The cause of death for Ana Clara Benevides Machado has not yet been announced. The office of Rio’s public prosecutor opened a criminal investigation and said Benevides’ body was being examined.

But concert-goers complained they were not allowed to take water into Nilton Santos Olympic Stadium despite soaring temperatures, and federal authorities announced that free water would be made available at all future concerts.

In a handwritten note shared on her social media, Swift said she had a “shattered heart.”

“There’s very little information I have other than the fact that she was so incredibly beautiful and far too young,” the singer wrote of the young woman.

The show’s organiser, Time4Fun, said on Instagram that paramedics attended to Benevides after she reported feeling unwell. She was taken to a first-aid centre and then to a hospital, where she died an hour later, the statement from the Brazilian live entertainment company said.

Fans who attended the Friday show said they were not allowed to bring water bottles into the stadium even though Rio and most of Brazil have had record-breaking temperatures this week amid a dangerous and lasting heat wave. The daytime high in Rio on Friday was 39.1 degrees Celsius (102.4 degrees Fahrenheit), but it felt much hotter.

Apparent temperature — a combination of temperature and humidity — hit 59 C (138 F) Friday morning in Rio, the highest index ever recorded there.

Elizabeth Morin, 26, who recently moved to Rio from Los Angeles, described “sauna-like” conditions inside the stadium.

“It was extremely hot. My hair got so wet from sweat as soon as I came in,” she said. “There was a point at which I had to check my breathing to make sure I wasn’t going to pass out.”

Morin said she drank plenty of water but saw “a good amount of people looking distressed” and others “yelling for water.” She said she was able to get water from the sidelines of the area she was standing in, but that water was a lot harder to access from other parts of the stadium, “especially if you were concerned about losing your specific position.”

During the show, Swift paused her performance and asked from the stage for water to be brought to a group of people who had successfully caught the singer’s attention, according to Morin.

“They were holding up their phones saying ‘We need water,’” she recalled.