NEW YORK (Reuters) - Five-times defending champion Roger Federer and Russian Dinara Safina will be the top seeds at the U.S. Open when it begins next Monday, the U.S. Tennis Association said on Tuesday.

Tournament organizers followed the ATP and WTA rankings to determine the men's and women's singles seeds. The draw for the two-week event will be announced on Thursday.

Federer, winner of the 2009 French Open and Wimbledon titles, is the top seed at the U.S. Open for the fifth time. The Swiss is seeded ahead of number two Andy Murray, Australian Open champion Rafael Nadal at number three, Novak Djokovic, and Andy Roddick.

The 28-year-old Federer, who has won four titles this year, became the sixth man to complete the career Grand Slam following his triumph at Roland Garros in June.

Safina is followed by number two seed and defending champion Serena Williams, her sister Venus Williams at number three, 2008 Beijing Olympics singles gold medalist Elena Dementieva and 2008 U.S. Open runner-up Jelena Jankovic.

The 23-year-old Safina has won three titles this year, including her back-to-back victories at Rome and Madrid. But the Russian is 0-3 in grand slam finals.

(Reporting by Steve Ginsburg in Washington; Editing by Pritha Sarkar)