U.S. Open semifinalist Yanina Wickmayer was suspended for one year by a Belgian anti-doping tribunal Thursday, accused of failing to report her whereabouts to drug-testing officials three times.

The Flemish regional tribunal called the punishment "reasonable." Tribunal spokesman Koen Uman said the suspension takes immediate effect, but Wickmayer can appeal the decision.

The 18th-ranked Belgian has denied any wrongdoing and said on her Web site she planned to appeal to the Court of Arbitration for Sport. She is playing in a tournament in Bali this week.

Another Belgian tennis player, 2002 Wimbledon semifinalist Xavier Malisse, also was suspended by the tribunal for breaking the whereabouts rule.

Wickmayer's suspension came as a surprise, because a prosecutor recommended she receive only a warning for missing three tests over 18 months. The tribunal said Wickmayer's failure to live up to anti-doping rules required a suspension.

Wickmayer said last month she has had trouble with her password in the computerized system overseen by the World Anti-Doping Agency. She also said registered mail at her home could not be signed off on because she was traveling to WTA tournaments.

She has insisted she never missed an anti-doping test and her samples were always negative.

Wickmayer has enjoyed a breakthrough year, including her run to the semifinals at the U.S. Open after never before moving past the second round at a Grand Slam tournament. She won her first two tour titles at Estoril in May and at Linz last month.

The International Tennis Federation, which oversees the sport's doping program, said Thursday it would not comment until receiving official notification of the suspension.

The U.S. Tennis Association _ which oversees the U.S. Open _ declined comment, as did the WTA and ATP.