The head of the US Olympics Committee has resigned.

Scott Blackmun said he's stepping down, citing health concerns related to prostate cancer.

The sport body has faced months of criticism for its handling of a series of sex abuse scandals.

Reports allege he may have known about the allegations against former gymnastics doctor Larry Nassar as early as September 2015.

Despite the complaints, critics say he did not properly intervene.

Al Jazeera's Katia Lopez-Hodoyan reports.