Universal Music Group may be about to pull its music from Apple's iTunes store, according to industry rumours.

Reports in Billboard state that the music giant, which boasts artists including Elton John, The Killers, Eminem and Pavarotti, is considering pulling out of an agreement to sell its music through iTunes.

"Universal Music Group wants greater flexibility," says the unnamed source quoted in the report.

"If someone comes along with a new service or device and wants an exclusive at launch for three months for 10 per cent of Universal's top line product, Universal could not do that if they signed [a two-year] Apple deal.

"Universal Music Group does not have long-term agreements with other retailers. So why Apple?"

The move could be a sign of Universal holding fire on signing a long-term deal before the launch of Amazon's music download service, expected to launch later this year. Amazon already sells video downloads via its Unbox service. 

Nearly three-quarters of all online music sold is currently through the iTunes store.