Three men have been charged with terror offences over the discovery of a homemade rocket in a car.
Detectives investigating dissident republican activity have charged the suspects with possession of explosives with intent to endanger life, conspiracy to murder and possession of articles for use in terrorism.
The PSNI said three men, two aged 47 and a 40-year-old, are due to appear at Londonderry Magistrates Court on Monday.
A fourth man, aged 41, has been released.
The bomb, said to be similar to those used against security forces in Iraq and Afghanistan, was discovered in a car in Londonderry on Thursday, the night before US secretary of state Hillary Clinton arrived in Northern Ireland.
The explosively formed projectile (EFP) is also capable of penetrating armoured vehicles.
The bomb was found after police stopped a black Renault Megane car in the Westway area of the Creggan. Security chiefs claimed dissident republicans opposed to the peace process were planning an attack in the centre of the city of Derry, next year's UK City of Culture.