The world's top sports tribunal announced Wednesday South Korean swimmer Park Tae-hwan has filed an appeal against an Olympic ban over doping.

It's the first official declaration by the Court of Arbitration for Sport (CAS) regarding Park's legal battle against the Korean Olympic Committee (KOC). The 2008 Olympic champion in the 400m freestyle already revealed last month that he'd filed his appeal in April.

A KOC rule prohibits an athlete from representing the country for three years after the end of a doping suspension. After testing positive for testosterone, Park served an 18-month suspension that began retroactively on Sept. 3, 2014, and ended on March 2 this year. Park was left off the preliminary national swimming roster announced on May 11.

The CAS said Park is seeking "an urgent ruling" by July 8 that would potentially allow him to compete in Rio. The deadline to finalize the national swimming team is July 18.

Park's legal representatives previously told the South Korean media that they would press for an expedited ruling.

The CAS said it will announce the final decision when it is available but will make no further comment in the meantime. (Yonhap)