According to U.S. defense officials quoted by the Washington Free Beacon on Wednesday, China is developing a long-range cruise missile that can be hidden inside shipping containers and launched from civilian freighters, a type of ship China happens to own in abundance.

The missile is described as the land-attack version of a high-end anti-ship missile called the YJ-18C. This Chinese anti-ship missile is, in turn, a variation of a Russian system that could be disguised as a shipping container.

As the Free Beacon pointed out, the idea of turning cargo ships into missile launch platforms is not new, but it is especially worrisome in China’s case given its aggressive posture, the huge number of container ships it has access to, and its enthusiasm for buying up civilian port facilities as part of the Belt and Road trade and infrastructure initiative. Weapons disguised as shipping containers could be launched from civilian ports at military facilities, and could remain undiscovered for a very long time in storage.

“China operates or is building deep water ports in several strategic locations, including Bahamas, Panama, and Jamaica that could be used covertly to deploy ships carrying the YJ-18C,” the Free Beacon noted.

Analysts also feared China might pass its shipping-container missiles along to rogue-state clients such as North Korea and Iran.

Several of the experts quoted by the Free Beacon mentioned the possibility that the relatively short-range container-launched cruise missiles could be fitted with electromagnetic pulse (EMP) warheads, giving them the ability to disrupt electronic equipment and electric power within a few hundred miles of civilian ports and shipping lanes.