Police are urging people in Dungiven to remain vigilant following claims a second device has been left in the area.
A number of homes were evacuated during a security alert which began in the town on Saturday.
A viable pipe bomb type device was recovered on Sunday night.
Police say the three day long security operation began after a phone-call was made with a recognised codeword. It has now ended.
Four men, two aged 55 and a 22 and 35 year old, who were arrested in connection with terrorism offences yesterday following a number of searches at properties in Omagh, Derry and Dungiven remain in police custody.
