Police carrying out a routine inspection of a car at a highway checkpoint in Shanghai found two naval gun shells in the boot.
The copper-plated 100mm shells, about 1.2 metres long, were concealed in two separate packages.
They were spotted when officers at the suburban checkpoint passed them through an X-ray scanner.
The driver was quoted as telling police that they were decorative “handicraft” items that merely resembled shells and were gifts from a friend. He was placed in custody.
A preliminary investigation found the shells were not live and did not contain any explosives.
But police said military experts would carry out a more thorough investigation to determine the source of the shells.
According to publicly available information, the 100mm naval gun shells are for use in twin gun turrets widely installed on various classes of destroyers and frigates in the PLA Navy.