The tactic in question is the terrorists’ capability to conduct small boat water-borne improvised explosive device attacks. According to the DHS report, the most vulnerable marine sector is U.S. and Canadian passenger ferries and terminals, which present softer targets than major ports and other significant marine transport elements, the Citizen reports.

A January report by Defence Research and Development Canada paints a different picture – it says that the threat to Canada’s maritime borders had increased. The report analyzed the terror risk presented by millions of small boats in high-traffic border regions, such as the Great Lakes and the St. Lawrence Seaway, against bridges and nuclear power plants.

“Emerging threats are being signaled by events in other countries such as Colombia and Mexico where there is a growing use of submersibles or miniature submarines, partially submerged vessels (presenting a small radar cross section) and high-powered low freeboard vessels (Pangas),” the report says, as reported by the Citizen.

The Canadian report notes that the terrorist risk manifests in several forms, such as transportation of weapons of mass destruction, the use of small vessels to deliver IEDs, the smuggling of unwanted persons, as well as a platform for standoff weapons and attacks.

The report concludes that Canada has no coherent strategy for dealing with a growing national security threat posed by small boats in high-traffic border regions.

The Great Lakes marine transportation system includes eight states, two provinces and more than 32 million Canadian and U.S. citizens, the article says. The region produces 50 percent of all U.S. manufacturing output and two-thirds of Canada’s.