A new investigation by the Police Ombudsman of Northern Ireland has found Special Branch didn't provide all of the information they had to detectives investigating the 1998 Omagh bombing in county Tyrone.

The probe shows intelligence officials withheld details, like phone numbers, for security reasons.

The investigation concluded it wouldn't have prevented the attack, though, which killed 29 people.

The 1998 explosion in Omagh has been described as the worst single terrorist attack of the Northern Ireland troubles, coming just months after the Good Friday agreement.