“We get things wrong, and we’re constantly working to make sure that happens less often,” Facebook executive Monika Bickert said in a Guardian op-ed on Monday. “We put a lot of detailed thought into trying to find right answers, even when there aren’t any.”

The documents, which were obtained by the Guardian, run through how the company determines whether content is flagged as “disturbing,” removed or left on the site. They also list examples throughout thousands of pages, some of which contain disturbing language, that would still be allowed to remain on the website according to their guidelines.

Bickert said that moderation on such a high scale “is complex, challenging and essential.” She added that Facebook does not publish all of its moderation methods to discourage people from finding “workarounds.”

“The articles and the training materials published alongside this show just how hard it can be to identify what is harmful – and what is necessary to allow people ability to share freely,” Bickert said. On the leaked documents themselves, Bickert said, “We appreciate the Guardian showing how tough it can be to draw the lines.”

Facebook announced earlier this month it would hire an additional 3,000 moderators to help review inappropriate content.

The news comes after multiple violent incidents have streamed on Facebook Live, including a man being shot to death in Cleveland. Facebook CEO Mark Zuckerberg addressed the Cleveland murder at Facebook’s annual developer conference, saying: “We have a lot of work and we will keep doing all we can to prevent tragedies like this from happening.”