Uber’s chief security officer Joe Sullivan posted an update Wednesday about the company’s use of “Greyball,” providing some details about use of the software tool, which was revealed in a New York Times report last week. Greyball was part of a program Uber designed to help it identify users who violate the terms of service of its app, preventing them from securing rides.

The NYT’s report said that Uber used it to monitor and identify app use by regulators and appointed officials who were tasked with catching Uber in the act of violating local transportation rules where Uber’s model was prohibited. The company now says it’s specifically prohibiting use of the tool for monitoring regulators, and that it’s reviewing its use of Greyball overall.

Here’s the full statement from Uber, posted by Sullivan to its company blog:

We wanted to give everyone an update on “greyballing”. This technology is used to hide the standard city app view for individual riders, enabling Uber to show that same rider a different version. It’s been used for many purposes, for example: the testing of new features by employees; marketing promotions; fraud prevention; to protect our partners from physical harm; and to deter riders using the app in violation of our terms of service.

We have started a review of the different ways this technology has been used to date. In addition, we are expressly prohibiting its use to target action by local regulators going forward. Given the way our systems are configured, it will take some time to ensure this prohibition is fully enforced. We’ve had a number of organizations reach out for information and we will be working to respond to their inquiries once we have finished our review.