TOKYO, April 9 -- Japan is fighting back against online abuse of athletes and sports authorities have a warning for trolls planning to target competitors at this year's Asian Games: You are being watched.

Online abuse is felt by athletes all over the world, affecting their performances and mental health, leaving them fearing for their safety and even causing them to quit their sports.

Japan is no exception and efforts are belatedly being made to tackle the problem, from dedicated lawyers to teams monitoring social media for offensive posts.

"Even a single negative comment can cut deeply," Japanese Olympic Committee (JOC) official Misa Chida told AFP.

"Athletes don't want to see things like that, so a lot of them choose not to look at ...