French Open champion Roger Federer announced on his official website on Tuesday that he has pulled out of the Halle grass tournament in Germany.

"I am sorry to announce that I have decided to withdraw from this week's Gerry Weber Open in Germany," Federer said.

"I sincerely apologise to the tournament organisers, my competitors, and my fans in Germany. I only hope they will understand that I still feel emotionally overwhelmed and exhausted by the incredible events of the past few days."

A five-time winner on Halle's grass courts in the past six years, Federer was the biggest name in a draw which includes world number four Novak Djokovic and world number nine Jo-Wilfried Tsonga of France.

(Xinhua News Agency June 10, 2009)