Breitbart News, the outlet once led by U.S. President-elect Donald Trump's chief strategist, has been blocked by one of the largest advertising exchanges serving digital publishers due to hate speech.

AppNexus deactivated Breitbart News after an audit of the site's content determined that it violates the advertising exchange's code of conduct banning hate speech, spokesman Joshua Zeitz said on Tuesday.

Breitbart CEO Larry Solov said the company "always and continues to condemn racism and bigotry in any form," in an email statement.