Ch Insp Tony Callaghan said: "There were no arrests; however items were taken away for further examination."
The operation came as Stormont Justice Minister David Ford met senior police officers in the area to discuss the security threat.
The searches were carried out on Wednesday in the Galliagh area of the city.
The searches follow an attempt last month to murder a couple - who are both in the police - in Eglinton, and a bomb at the Probation Service in Derry in April.
Mr Ford said he was satisfied police had resources to deal with the threat.
"Since I became minister of justice, the threat to police and prison officers has been regarded as severe throughout Northern Ireland, so it is clearly significant," he said.
"But what I also heard about this morning was very good positive constructive work, policing with the community, solid community engagement right across the Derry and Strabane district.
"I think this is an indication of the very good work being done by the police despite the threat."
Sinn FÃ©in Policing Board member Gerry Kelly criticised the deployment of the Army during the security operation, and said he would raise the issue with the chief constable.
"Let's not pretend that this not a big issue - this is a stretching out of the use of the British army," he said.
Ch Insp Callaghan said the Army was deployed upon the advice of PSNI specialists about the dangerous nature of the searches.
"We were looking for munitions or explosives, and because of those risks, the Army are the properly trained people to deal with that," he said.
Searches have been carried out by police investigating dissident republican activity in Londonderry.