The World Anti-Doping Agency has appealed against the decision to clear world number one Jannik Sinner of blame after he twice tested positive for a banned substance.

Wada said last month's ruling by an independent tribunal to find the Italian had no fault or negligence was "not correct under the applicable rules".

It has appealed to the Court of Arbitration for Sport (Cas) and says Sinner should be banned for "between one and two years".

Sinner, 23, is currently playing Roman Safiullin in the last 16 of the China Open in Beijing.

The case had been presented to a tribunal by the International Tennis Integrity Agency (ITIA).

Sinner was cleared of any wrongdoing after twice testing positive for low levels of a metabolite of clostebol - a steroid that can be used to build muscle mass - during the Indian Wells tournament in March.