~~ Gaga to undergo hip surgery ~~

Washington: Lady Gaga has canceled the rest of her 'Born This Way Ball' tour due to a hip problem that requires surgery, Live Nation Global Touring said on Wednesday.

In a statement, the tour operator said the superstar singer has a labral tear of the right hip.

"She will need surgery to repair the problem, followed by strict down time to recover," said the statement. "This, unfortunately, will force her to cancel the tour so she can heal."

In a series of tweets Tuesday, Lady Gaga said she had been hiding a show injury and chronic pain for some time, and that it had worsened over the past month.

"I hid it from my staff, I didn't want to disappoint my amazing fans," she tweeted.

The latest tweet had described her condition as a case of synovitis, an inflammation of the joints.

Live Nation said refunds for the canceled performances will be available from Thursday.

At the time of the announcement, Lady Gaga had 19 performances scheduled through March 20 at concert venues across the United States.