Police are investigating the armed robbery of a service station in Sydney’s south west.

Just after 12.30am (Thursday 12 September 2013), two men entered a service station on Rookwood Road, Yagoona, armed with a knife.

The men threatened the male attendant before fleeing with a sum of cash.

They were last seen getting into a silver-coloured SUV, similar to a RAV4, on Rookwood Road.

Police were alerted and officers from Bankstown Local Area Command established a crime scene that was examined by specialist forensic officers.

An investigation into the incident is underway and police are appealing for any witnesses, or anyone with information that may assist, to come forward.

Both men were wearing dark clothing and had their faces heavily disguised.