Simona Halep has been suspended indefinitely after testing positive for a prohibited substance.

The International Tennis Integrity Agency (ITIA) announced on Friday that two-time Grand Slam champion Simona Halep has been provisionally suspended after testing positive for a banned substance.

"Simona Halep, a 31-year-old Romanian tennis player," the body said in a statement, "has been provisionally suspended under Article 7.12.1 of the 2022 Tennis Anti-Doping Programme (TADP)."

The world No. 9 tested positive for the anti-anaemia drug Roxadustat at the US Open in New York and has been suspended indefinitely.

Halep, who won the French Open and Wimbledon the following year, is the most famous tennis player to fail a drug test since Maria Sharapova six years ago.

The Romanian was eliminated in the first round of the US Open by Daria Snigur, ending her season last month after nasal surgery.

"Today begins the hardest match of my life: a fight for the truth," Halep wrote on her social media channels.

"I was informed that I tested positive for a substance called Roxadustat in extremely low quantities, which was the biggest surprise of my life."

Halep went on to say that she is "completely confused and betrayed" and that she "will fight until the end to prove that I never knowingly took any prohibited substance."

"It is not about titles or money. It's about honor and the love story I've built with tennis over the last 25 years "She went on.

Halep turned professional in 2006 and made her WTA main draw debut at the Andalucia Tennis Experience in 2010.

She lost her first Grand Slam final in 2014, at the French Open, to Maria Sharapova, who later in her career tested positive for the banned substance meldonium.

After losing finals at Roland-Garros (2017) and the Australian Open (2018), Halep won her first major by defeating Sloane Stephens in the 2018 French Open, and she went on to defeat Serena Williams to win her first Wimbledon title in 2019.