Three Taylor Swift concerts have been canceled after two men were arrested in connection with an alleged terror plot said to have targeted the events.

Swift was due to perform at Vienna's Ernst Happel Stadium on Thursday, Friday and Saturday.

But event organizer Barracuda Music said in an Instagram post on Wednesday that "we have no choice but to cancel the three scheduled concerts for everyone's safety" after "confirmation of the planned terrorist attack".

The popstar's website also appears to reflect the cancellation.

Under the "tour" tab, shows in the Austrian capital now have a note saying: "All tickets will be automatically refunded within the next 10 working days."

Two men have been arrested in connection with the suspected terror plot, which police say targeted major events in Vienna, including upcoming Swift concerts.

US officials familiar with the investigation told Sky News' US partner NBC News that Austrian law enforcement is still searching for an additional individual or individuals who may have knowledge of the alleged plot.

The suspects had been under surveillance for some time and were known to Austrian authorities, the officials added.

According to Vienna state police director Franz Ruf, one of those arrested was a 19-year-old man who allegedly pledged his allegiance to the IS terror group.

"During our investigations, we identified preparatory actions and noticed that the 19-year-old suspect had a particular focus on the Taylor Swift concerts in Vienna," said Ruf.

His arrest was made in the early hours of Wednesday, while the second arrest was made in Vienna later in the day.

Police said both men had been radicalized online.

They allegedly had specific and detailed plans to carry out the attacks on the concerts, which were expected to attract crowds of up to 65,000 each day.

During the arrest of the 19-year-old Austrian, in Ternitz, Austria, officers found chemical substances that are being investigated as possible components of a bomb.

It was said that he was unlikely to have been able to obtain all the components needed for a bomb before the events of the weekend, but Austrian authorities decided to arrest the two in order to prevent them from carrying out an attack using other means .

According to NBC News, after officials announced a strong security plan for the concerts, Swift's team said they would be canceled.

Austrian Chancellor Karl Nehammer described the cancellation as a "bitter disappointment" but said a "tragedy [was] averted".

He said the situation surrounding the alleged plot was "very serious", but thanked the authorities for their decisive action./Skynews/