Facebook is prohibiting developers from using the massive amount of data it collects on users for surveillance.

This includes using such data to monitor activists and protesters.

The company said yesterday that it is making an existing policy “explicit.” Facebook says it has already taken action against developers who created or marketed tools meant to be used for surveillance.

Last fall, the American Civil Liberties Union obtained records that Facebook and its Instagram service provided user data access to Geofeedia, which develops a monitoring product marketed to law enforcement.