Maria Sharapova has revealed she has failed a drugs test at this year's Australian Open. The 28-year-old star confirmed the surprising news that she tested positive for meldonium during a hastily-arranged news conference in Los Angeles.

The grand slam-winning player said she had been taking the substance as a form of medication for a variety of health issues since 2006.

Sharapova received a letter in December which confirmed meldonium had been added to the list of banned substances, but claimed she had not read the letter thoroughly. Sharapova continued to use the meldonium - a blood flow drug - at the Australian Open this year, after the changes had been introduced.

"I received a letter on 22 December from the World Anti Doping Agency for the changes next year and where the tests will be with a link to the changes for 2016 and I did not look at that list," she explained to the assembled media.

The Russian accepted full responsibility for the failed test and insisted she intended to continue her trophy-laden tennis career, assuming she was allowed to do so by the sport's authorities. "I know that with this, I face consequences and I don't want to end my career this way and I hope that will have a chance to play again," she said.

Meldoniun improves exercise capacity in patients with chronic heart failure, although it can also give an advantage to healthy athletes. Sharapova - who is currently ranked seventh in the world - insisted she never had any intention to cheat. The former Wimbledon champion also said she is not yet aware of the sanctions she will face.

During the course of her career, Sharapova has won all four grand slam titles and a silver medal at the London Olympics in 2012. Away from the court, she has featured in a number of modelling assignments with the likes of Nike, Prince, and Canon, thereby making her one of the highest-earning athletes in the world.

In recent years, however, her career has been blighted by a series of injuries and the Australian Open is the only tournament she has played in 2016.