Serena Williams has labelled Russian tennis federation president Shamil Tarpischev's comments about her and her sister Venus "sexist, racist and bullying".

Tarpischev, who is also the Russian Davis and Fed Cup captain and a member of the International Olympic Committee, referred to world number one Serena and Venus as "the Williams brothers" on Russian television.

He has been fined $25,000 and suspended from any involvement with the Women's Tennis Association for a year while the governing body is also seeking his removal from his position as chairman of the board of the Kremlin Cup for a year.

Williams is preparing to play in the season-ending WTA Finals in Singapore, where both she and Russia's Maria Sharapova addressed the issue.

Williams, quoted in the New York Times, said: "I thought (the comments) were very insensitive and extremely sexist as well as racist at the same time. I thought they were in a way bullying.

"I've done the best that I can do, and that's all I can say. So I just wasn't very happy with his comments. I think a lot of people weren't happy as well.

"The WTA and the USTA (United States Tennis Association) did a wonderful job of making sure that - in this day and age, 2014 - for someone with his power, it's really unacceptable to make such bullying remarks."

Sharapova, Russia's five-time grand slam champion, backed up her fellow professional.

She said of Tarpischev's remarks: "I think they were very disrespectful and uncalled for, and I'm glad that many people have stood up, including the WTA.

"It was very inappropriate, especially in his position and all the responsibilities that he has not just in this sport, but being part of the Olympic committee. It was just really irresponsible on his side."

Stacey Allaster, chairman and CEO of the WTA, on Saturday called for Tarpischev to apologise both publicly and personally to the Williams sisters.

He subsequently paid tribute to the pair's playing careers, which have brought them a combined 25 grand slam singles titles, but was insistent that his derogatory comment was a joke and should not be the focus of such attention.

In a statement from the Russian Tennis Federation on Saturday, Tarpischev said: "Serena and Venus, of course, are outstanding athletes. They show the highest class of tennis. You can see - they are on a different level.

"The Williams sisters will always stand out on the tour and in the sport as a whole due to their achievements and their skills. They represent strength and perseverance and achieved results that for a long time will be considered as the highest bar for other players.

"I regret that that joke, which when translated into English has been taken out of humorous context, was the focus of so much attention. I do not think that this story deserves such hype. After all, everything said on the air was said without malice."