Thousands of Islamic State documents containing the personal details of fighters for the terror group have been leaked, according to reports.
More than 22,000 documents show the addresses, telephone numbers and family contacts of those who have signed up to join ISIS.
The information reportedly shows that people from 51 countries, including the UK, had filled in 23 question forms for IS.
The address book was described as an absolute gold mine of information of enormous significance and interest to very many people, particularly the security and intelligence services.