Tour organisers have revealed that Rihanna may be forced to axe a string of American tour dates, due to poor ticket sales, and tour managers are encouraging local radio stations to do giveaways.

It is the second time that the 'S&M' star has been forced  to tour cancel dates. Last year the Barbadian singer canceled dates on her 'Last Girl on Earth' tour due to low demand.

Approximately 3,700 tickets have allegedly been sold for one venue, but at least 15,000 will need to be shifted in order to break even.

Watch Rihanna talking about her American Vogue Cover shoot with Annie Leibovitz, below: