The 22-year-old, who has a reputation as a wild woman in Britain, was detained for five hours and questioned at Los Angeles International Airport when she arrived from Australia on Aug. 6.

Her working visa was revoked by U.S. authorities and because the reinstatement process is taking longer than expected, she won't be able to launch her tour Sept. 6 in San Diego.

The singer said she had no idea why she lost her visa. Media reported she was arrested in March for an alleged assault on a photographer in London airport. She received a warning from police but was not charged with any crime.

"I am so disappointed that I won't be able to come to the States at this time," Allen said in a press release.

"I was really looking forward to playing these shows and being part of the Video Music Awards. I want my fans to know I'll be back as soon as I possibly can!"

There's no word yet on when the concerts -- which were set to take place in San Francisco, Las Vegas and Seattle, among other cities -- might be rescheduled.

Allen, whose debut single "Smile" went to number one on the UK music charts, had been due to tour the United States in May and June. But she canceled the concerts in April, saying she was tired and not performing as well as she could.