Londonderry bomb alert: 'Mindless and reckless' attack
4 March 2013 Last updated at 11:49 GMT
Four live mortar bombs "primed and ready to go" have been intercepted by police in a van in Northern Ireland.
The van had its roof cut back to allow the mortars to be fired. Police believe the target was a Londonderry police station.
Three men in their 30s have been arrested following the overnight operation in Derry which police have linked to dissident republicans.
At a press conference, Chief Superintendent Stephen Cargin described the incident as "a reckless attack by dissident republicans to murder police officers in the city of Derry".