The airport's security comes under the regulatory purview of the Airport Police Division of the Singapore Police Force. The day to day discharge of security functions at the airport are performed by auxiliary police forces including Aetos Security Management, Certis CISCO and SATS Security Services, of which Aetos and SATS Security Services are affiliated to the ground handling companies of Dnata and Singapore Airport Terminal Services respectively. On 29 April 2008, CAAS then signed its biggest single security contract for all airport related security services by engaging Certis CISCO to provide security services at Changi Airport, as well as Seletar Airport, Changi Airfreight Centre, and the Singapore Air Traffic Control Centre.It involves the deployment of about 2,600 Certis Cisco personnel, including armed Auxiliary Police Officers and unarmed aviation security officers to perform tasks including screening checked baggage, controlling access to restricted areas, and screening passengers before they board their aircraft.