Facebook made a "mistake" when it asked in a survey whether people who request sexual pictures from children should be able to use the site, a company executive said.

The survey asked some users including The Guardian digital editor Jonathan Haynes on Sunday how Facebook should handle certain behaviors, The Guardian reported. 

Haynes tweeted images of the survey, which he said popped up in his Facebook account. One question asked: "In thinking about an ideal world where you could set Facebook's policies, how would you handle the following: a private message in which an adult man asks a 14-year-old girl for sexual pictures."

The response options included "this content should not be allowed on Facebook, and no one should be able to see it" and "this content should be allowed on Facebook, and I would not mind seeing it." There was no response stating that Facebook should contact law enforcement or child protection services. 

Guy Rosen, vice president of product at Facebook, responded to Haynes in a tweet.

"We run surveys to understand how the community thinks about how we set policies. But this kind of activity is and will always be completely unacceptable on FB. We regularly work with authorities if identified. It shouldn't have been part of this survey. That was a mistake."

The social networking giant has mechanisms in place to report harmful content, but they often haven't been enough. Facebook has been slammed for failing to remove sexual child images from its site, even after they've been reported. It has also grappled with monitoring other content such as violence streamed through its Facebook Live feature.

Facebook didn't immediately respond to CNET's request for comment.

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