NEW YORK, Aug. 6 (Xinhua) -- Tournament officials Venus Williams pulled out of next week's Cincinnati Open tennis tournament due to knee injury.

Tournament director Bruce Flory said on Friday that officials wish Williams could compete in this year's tournament, but that the field remains the strongest it's ever been.

Williams said in a statement that she returned to her normal practice schedule the last three weeks and began to feel pain in her left knee.

Williams says she regrets not being able to compete in Cincinnati and her medical advisers recommended that she not play until she is pain free.