Bayern Munich said winger Arjen Robben will be unable to train for 10 days following an operation.

Team doctor Hans-Wilhelm Mueller-Wohlfahrt said Robben developed a further complication to his long-standing groin injury.

''This was successfully operated on by Dr. Tomas Hoffmann in Munich's Maria-Theresia clinic this morning,'' Mueller-Wohlfahrt said.

Robben returned from the Netherlands' training camp on Thursday, after he was ruled out of the European Championship qualifiers against Moldova and Sweden.

Netherlands coach Bert van Marwijk said it was ''a complicated, stubborn injury.''

Robben has been beset by back and groin problems this season.

The latest setback is likely to rule him out of action for at least three weeks.