Fire crews were tied up for almost half an hour after responding to a hoax call in Bargoed.
A South Wales Fire and Rescue Service crew from Aberbargoed responded to a malicious call, reporting a person locked in Bargoed Job Centre Plus, on the High Street, at around 11pm on Thursday August 4.
Firefighters realised that the report was false, and no one was locked in the building, after around 26 minutes.
Jennie Griffiths, Head of Fire Control at South Wales Fire and Rescue Service, said: “Malicious callers are not only an enormous drain on resources but their thoughtless behaviour endangers the lives and safety of the public.
“Firefighters must respond to every emergency call that is made. If they arrive at an address and find out that it’s a hoax, it may delay them from attending a serious emergency incident, where they may be needed to rescue someone trapped in a house fire or road traffic collision.”