The UK government has unveiled a tool it says can accurately detect jihadist content and block it from being viewed.

Home Secretary Amber Rudd told the BBC she would not rule out forcing technology companies to use it by law.

Ms Rudd is visiting the US to meet tech companies to discuss the idea, as well as other efforts to tackle extremism.

In London, reporters were given an off-the-record briefing detailing how ASI's software worked, but were asked not to share its precise methodology. However, in simple terms, it is an algorithm that draws on characteristics typical of IS and its online activity.