Mistakes by US authorities allowed terrorists to board flights, according to a watchdog investigation.
A "small but significant number" of suspected or known terrorists were able to fly because their new identities had not been updated on the nation’s ‘no-fly’ list.
This was down to miscommunication between the US justice department’s ‘Witness Security Program’ and the FBI.
As a result of the investigation, the justice department said it has now changed its information sharing and had thoroughly screened all participants on the programme.
The programme had protected the identities of those who co-operated in prosecutions for the 1993 World Trade Center bombing, the 1995 bombing in Oklahoma City and the 2009 New York City subway suicide-bomb plot.
The report by the justice department inspector general was completed last year but was kept secret until the justice department could take steps to close the security gaps.
