At the SXSW festival on Monday, the mayor of London, Sadiq Khan, asked Facebook and Twitter to do more to combat hate speech.
During his talk, Khan read hateful social-media posts about himself.
He suggested that tech companies should face fines if they don't remove hate speech quickly.
During his talk, the mayor read racist tweets about himself.
"I say kill the mayor of London and you'll be rid of one Muslim terrorist," Khan read aloud. "I'd pay for someone to execute Sadiq Khan."