The US Federal Bureau of Investigation (FBI) is planning to develop an application that can track the public's postings to Facebook, Twitter and other social networks, in order to aid how it predicts and reacts to criminal behaviour, including public disorder and terrorism.

An FBI request for information document has been published, asking potential contractors to contact the bureau by 10 February. The FBI wants respondents to the document to outline how they would build such a system and how much it would potentially cost.

The bureau said the system it wants must be able to automatically search "publicly available" material from Facebook, Twitter and other social media sites for keywords of interest. FBI agents would be alerted if the searches come up with evidence of "breaking events, incidents, and emerging threats".

Agents would have the ability to display any information on a map, and they could then add other layers of information, including past incidents and locations of important buildings like embassies and military installations.

The document notes that agents need to "locate bad actors and analyse their movements, vulnerabilities, limitations, and possible adverse actions".