Earlier this week, Twitter rolled out new tools to help users combat abuse. That seemed to stir up a hornets' nest of white supremacists, as some Twitter users started noticing promoted tweets for those hate groups on their timelines. The company initially denied the veracity of those reports, but now CEO Jack Dorsey is offering up an apology and laying the blame on Twitter's automated approval systems.

We made a mistake here and we apologize. Our automated system allowed an ad promoting hate. Against our policy. We did a retro and fixed! https://t.co/7gvycmzpsm — 🚶🏽jack (@jack) November 17, 2016