Police in Derry were backed up by military personnel during a number of searches in Galliagh area of the city today.
A number of items were taken away for further examination.
The military presence was requested due to the suspected presence of munitions or explosives.
No arrests were made.
Chief Inspector Tony Callaghan said: “Searches carried out in connection with the investigation of serious crime in Londonderry have concluded.
“There were no arrests; however a number of items were taken away for further examination.
“Due to the suspected presence of munitions or explosives, military specialists were deployed in support of police.
“The role of these military personnel is to search for munitions and explosive devices which, if located, will then be dealt with by the army bomb disposal officer. The military used are specifically trained in this type of high risk search, thus ensuring that such searches are conducted in as safe a manner as possible.”