The statement added: “All tickets will be automatically refunded within the next 10 days.”
Earlier, Austria's Public Safety Commissioner Franz Ruff said a 19-year-old Austrian citizen was arrested in Ternitz, Lower Austria, on Wednesday morning.
He said a second arrest was made in Vienna in the afternoon, but gave no details about the suspect.
“Based on our current investigation, both suspects were radicalized via the Internet,” Mr Loop said.
He said the 19-year-old boy had “pledged allegiance” to the so-called Islamic State in early July.
A massive police operation was launched in Ternitz, where the 19-year-old lived. Several nearby homes were evacuated while his house was searched.
Mr Loop said the chemicals were found and were being investigated.
Vienna police chief Gerhard Fürstl said he expected an average of 65,000 people to attend the concert each day, with another 22,000 fans expected outside the venue.
The investigation is ongoing.
