WASHINGTON -- The United States must introduce closer surveillance of small boats, which constitute the most serious threat to maritime security, the head of the country's coast guard said.
Admiral Thad Allen said that despite public opposition to increased registration and tracking of largely-recreational vessels, "we need to be moving in that direction."
Allen, who steps down as US Coast Guard commandant next May, acknowledge there was currently no "credible threat" of a small boat-launched attack on the United States, but said "it should not take an event" to prompt a debate on more restrictive measures.
In the wake of the September 11 attacks, the US government has introduced a series of measures to improve port and cargo security, but Allen said small boats were still a "vulnerability."
Currently, boaters on vessels smaller than 300 gross tons (272 gross tonnes), up to about 70 feet (21 meters) long, are largely free to move around unrestricted and without transponders, while small aircraft traffic is closely monitored and controlled.
"The water is opaque," Allen said, pointing to vulnerabilities in the 90,000-plus miles (150,000 kilometers) of US maritime borders.
The maritime threat was thrown into sharp relief in November 2008, when 10 heavily-armed gunmen launched attacks on several Mumbai landmarks, killing 166 people and injuring 300 more.
The attackers arrived by sea to India on a hijacked boat and entered Mumbai by rubber dingy.
The Department of Homeland Security, which oversees the coast guard, has been looking into other small boat-based threat scenarios, including their combined use with portable surface-to-air weapons to attack airports and with improvised explosive devices.
In 2004, Nathan Bruckenthal became the first coast guardsman to die in combat since the Vietnam War, when he and two sailors tried to board a bomb-rigged boat in Iraq that was then detonated.
Allen said that heated discussions were being held on how to deal with the threat, with "very diverse opinions" on how to proceed.
"We are working on a strategic plan to deal with small vessels with CBP (the Customs and Border Protection agency)," he said.
Although Allen said moving forward was "extremely problematic," he argued there were legitimate grounds to restrict access to certain areas, such as the Houston Ship Channel, a vital route for the US oil trade.
Fifty-five water-accessible US ports and facilities have been identified as particularly vulnerable or important and would be "hardened," he added.
There are signs the threat may be increasing.
In recent months, the coast guard chief said there had been an "uptick" in the number of small boats arriving to the United States from Mexico, where authorities are engaged in a bloody battle to stop the flow of illicit drugs.
He said more drug-laden vessels had recently been headed to San Diego and were in the Gulf of Mexico as the border tightened.
Much of the cocaine destined for the United States from Colombia is transported in small "Go Fast" boats through Central America.
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