The heroin was found stuffed into the car's gas tank. PHOTO: TOLLVESENET

A 25-year-old man from Serbia was caught in Janaury with 12.5 kilos of heroin stuffed into his car's gas tank.

"The car was pulled aside for a check, and after a chat with the man, the customs officials decided to check the car in the garage," Wenche Fredriksen of the Customs Region East told Norwegian Broadcasting (NRK).

A dog specially trained to sniff out narcotics reacted immediately and indicated the area of the vehicle where the heroin was hidden. It was eventually found in the French-registered car's gas tank.

An announcement of the seizure was delayed, she said, because police didn't want the news to jeopardize their investigation.

The man was said to be alone in the car and hasn't been arrested for narcotics smuggling earlier.

He's being held in remand custody until his case can be heard in court.