US sportswear maker Nike said Monday it was halting its relationship with Maria Sharapova, after the tennis star announced she had tested positive for a banned substance.
"We are saddened and surprised by the news about Maria Sharapova," Nike said in a statement. "We have decided to suspend our relationship with Maria while the investigation continues."
The 28-year-old Sharapova, a five-time grand slam champion, will be provisionally suspended starting 12 March, the International Tennis Federation (ITF) said.
She is the seventh athlete in a month to test positive for meldonium, which is used to treat diabetes and low magnesium, and was only banned by the World Anti-Doping Agency as of 1 January.
"I made a huge mistake. I let my fans down and I let the sport down," said Sharapova, a teenage tennis prodigy who became the third-youngest Wimbledon champion. "I take full responsibility for it."
"I know that with this I face consequences and I don't want to end my career this way. I really hope that I will be given another chance to play this game," former world No 1 Sharapova told a news conference in a downtown Los Angeles hotel.
Hours after the announcement, one of her biggest sponsors, Nike, said it had suspended its relationship with her and released the statement.
With inputs from agencies