Serena, Venus Williams out of doubles at Wimbledon; no reason given by tournament referee

Serena and Venus Williams have pulled out of women's doubles at Wimbledon.

The tournament referee's office announced the withdrawal Tuesday, but did not give a reason.

The Williams sisters have won 13 Grand Slam doubles titles as a pair, most recently at Wimbledon in 2012.

Both won first-round singles matches Monday.

In doubles at the All England Club last year, they stopped after three games in the second round, because Serena was ill.

Misaki Doi of Japan and Stephanie Vogt of Liechtenstein replaced the Williams sisters in this year's draw.

Dominika Cibulkova and Anna Karolina Schmiedlova also pulled out of doubles on Tuesday.