Olympic hammer throw champion Koji Murofushi pledged Wednesday he will continue to fulfill his duties as the Japan Sports Agency commissioner following news that he is battling illness.

A source with knowledge of the matter said the 46-year-old Athens Olympic gold medalist is being treated for a disease, something Murofushi declined to elaborate on, citing privacy. Gossip magazine Shukan Shincho reported in its online edition he is suffering from a malignant brain lymphoma.

"I'll try not to be influenced by it and carry out my duties properly. I ask for your support," Murofushi told reporters.

The report said the JSA commissioner has been fighting the disease since last autumn, but that he is expected to recover.

"I've been working to ensure it does not pose a problem for my public duties, and I will continue to give my all for the successful staging of the Tokyo Olympics and Paralympics," Murofushi said in a JSA statement.

Murofushi, who won a gold medal in the hammer throw at the 2004 Athens Olympics and a bronze medal at London in 2012, was sports director for the Tokyo 2020 Games, postponed a year due to the coronavirus pandemic, until being named Commissioner of the Japan Sports Agency in September. He has continued to take part in regular press conferences, the last occurring on March 23.

Recent photos on his social media have shown him meeting people in his office and posing as if to throw a javelin.

Murofushi comes from a sports-oriented family. His father was an Olympics hammer thrower and his Romanian mother competed internationally in javelin, while his sister also is a retired hammer thrower.

The goateed, soft-spoken Murofushi is a popular figure in Japanese sports, and reports of his illness were trending on Twitter, with many users in shock.

"Please, don't worry about work. Just take care of yourself," one wrote.