Three men have been arrested after police foiled what is believed to be a planned bomb attack by dissident republicans.
Police Service of Northern Ireland officers rammed a van close to Derry city centre in an apparent undercover operation.
Two men were detained at the scene and a third was held later in follow-up searches.
It is not known what type of device was found in the van - one report claimed it was a mortar bomb - but sources claimed it was "significant".
More than 100 homes had to be evacuated when the police moved in on the vehicle close to the junction of Letterkenny Road and Foyle Road.
Several people who had to leave their homes on Sunday night were elderly and a security operation was still going on at breakfast-time.
The three men in custody are all in their 30s.
Dissident republicans opposed to Sinn Fein's peace process strategy have been under 24-hour police surveillance amid fears of new attacks in Derry, this year's UK City of Culture.
At one stage on Sunday night, police diverting traffic away from the scene were attacked by people throwing stones. At least one petrol bomb was also thrown.
Pat Ramsay, an SDLP member of the Northern Ireland Assembly, said it was clear that a viable device had been recovered. "It looks as if police kept death off the streets of Derry," he added.