Detectives are trying to track down a pair of armed robbers who stole money from a cash delivery van in Poole last night.

Police say two security guards were treated for minor injuries after being attacked with a knife and 'a heavy instrument' ... outside the Nationwide on Ashley Road in Parkstone at about 10-20 p-m.

Armed officers - helped by the force helicopter - carried out an unsuccesful search for the offenders - and are appealing for witnesses.