Moscow: Four-time world champion Russian swimmer Yulia Yefimova said on Monday that she is going to challenge her suspension from competition for suspected doping. "Currently we are preparing for hearings of my case. We intend to prove that I have not violated the anti-doping rules," Xinhua quoted Yefimova as saying. Last week, the All-Russian Swimming Federation (ARSF) confirmed that the International Swimming Federation (FINA) has temporarily suspended the sportswoman from competitions due to possible anti-doping rule violation after testing positive for use of meldonium drug. Meldonium, also known as mildronate and used to treat various heart diseases, has been banned by the World Anti-Doping Agency (WADA) from this year. Yefimova said she did not receive any warnings that meldonium had been included in the banned list from January, neither from Russian, nor from foreign organisations, in electronic, or in oral form. "It was legal the last time I used Meldonium for medical reasons," she said, adding that she was surprised that tests conducted more than a month later showed presence of the drug. However, ARSF president Vladimir Salnikov denied the statement. "The Federation has notified in advance all athletes in accordance with the rules. The information has also been published on the official website of the Federation," R-Sport, a sports division of RIA Novosti news agency, quoted Salnikov as saying. More than 10 Russian athletes, including tennis star Maria Sharapova, have so far been tested positive for meldonium. Russian President Vladimir Putin on Wednesday called on the government to improve the efficiency of doping prevention, and to toughen penalties for violations of anti-doping rules. Yefimova said she was optimistic about her fate and would continue training in expectation that she would be able to participate in the Rio Olympic Games.