We were dumbfounded to hear that Sony recently publicly stated that they 'respect' us, after they have gone to such extremes not to pay us what they contractually owe us

Dixie Chicks

Sony dismissed the claim as a "sham".

The company said the group were using the action as a way of terminating their recording deal after two unsuccessful attempts to increase their earnings.

In July, Sony brought its own action after the Dixie Chicks said they wanted to stop recording for the label.

The band - made up of Natalie Maines and sisters Martie Seidel and Emily Robison - issued a statement explaining why they were taking Sony to court.

"This is about people keeping their word," said the group.

"We were dumbfounded to hear that Sony recently publicly stated that they 'respect' us, after they have gone to such extremes not to pay us what they contractually owe us.''

Deal

The Dixie Chicks have been signed to Sony since 1995 and their two albums Wide Open Spaces and Fly have sold nearly 20 million copies in the US.

The Dixie Chicks claim that Sony underpaid them at least $4m (�2.7m) in royalties on the albums over the past three years.

Courtney Love sued Universal this year

They allege that the company held back royalties in more than 30 different cases of fraudulent practice.

When making its own legal claim against the group in July, Sony said it could lose up to $100m (�67m) if the group did not fulfil a five album deal with the company.

The group are just one of a number of recording stars to take legal action against the record industry over alleged unfair practice.

In February, for example, Courtney Love sued Universal Music to get out of her contract and highlight "repressive and unfair working conditions".