DAKAR, Senegal -- U.S. Navy sailors may board thousands of commercial ships in international waters to search for weapons of mass destruction under a landmark pact between the United States and Liberia, the world's No. 2 shipping registry.
This week's accord -- expected to become a model as Washington seeks other two-country deals authorizing searches on the high seas -- comes amid fears that terror networks would use ships for attacks, taking advantage of comparatively lax security on the waters after crackdowns in the skies.
Liberia, an American-founded West African nation emerging from nearly 15 years of civil war, has held a U.S.-based shipping registry since 1949 and now hosts more than 2,000 foreign vessels.
It ranks second only to Panama in total shipping tonnage in U.S. ports, under so-called flags of convenience that offer cheap fees and easy rules. One-third of America's imported oil arrives in the United States on Liberian-flagged tankers.
With the pact, American forces may board and search any Liberian-registered foreign ship they suspect of carrying weapons of mass destruction, their delivery systems, or related material, State Department spokesman Richard Boucher said in Washington.
"It's based on the need to stop the proliferation in weapons of mass destruction and means to deliver them," Boucher said Friday.
Wednesday's pact was the first of its kind, Boucher said. He confirmed Washington was seeking similar deals with other nations, but declined to identify them.
With commercial ships transporting 80 percent of the world's traded goods, security experts worry that vessels, ports and other links in the maritime economic chain might make tempting targets. A terrorist attack could sink a ship, cripple a port, panic markets and disrupt trade.
Suicide attacks killed 17 sailors on the American destroyer USS Cole in Yemen in 2000 and a crewman on the French oil tanker Limburger off Yemen's coast in October 2002. Terrorists tried and failed to attack another U.S. destroyer before succeeding against the Cole, and authorities in Singapore and Morocco have recently foiled similar plots.
Ships can also be used to transport weapons or nuclear components for use on land.
Explosives used to blow up two U.S. embassies in Africa in 1998 and nightclubs in Bali in 2002 allegedly were brought in by ships. And in October, British and American authorities intercepted a shipment of nuclear components bound for Libya on a German freighter, helping prod Libya to reveal -- and renounce -- its nuclear weapons program in December.
Without the U.S.-Liberia pact, Liberian-flagged ships carrying suspect materials had to be shown to be breaking international law, or enter U.S. waters, before the United States could act unilaterally, experts say.
If the U.S. Navy wanted to interdict a ship flying a foreign flag, it had to work through diplomatic channels with the government where the ship is registered -- a time-consuming process, they said.
"With this accord, the U.S. and its allies can feel more secure, and our ships can feel more secure under the U.S. security umbrella," Yoram Cohen, head of Liberia's shipping registry, said in a statement.
The registry said U.S. authorities still must contact it before boarding any vessel.
But shipping industry analysts said the United States was already frequently stopping and searching vessels on the high seas at will.
"It puts existing practice on a friendlier footing," said David Osler of the respected Lloyd's List shipping daily.
"The U.S. Navy will continue to board vessels when they want to," Osler said. "But at least in the case of Liberia, they'll be able to do it legally."
The United States says the accord is based on similar pacts to block narcotics trafficking.
"I think it's likely to be replicated with other flags," said Chris Austen, CEO of London-based Maritime and Underwater Security Consultants.
"It's following the path that the U.S. has been following for a while of setting up bilateral agreements rather than going through the painful process of reaching a multilateral agreement," Austen said.
Panama, the top country for flags of convenience, has no such agreement and isn't currently negotiating one, Deputy Foreign Minister Nivia Rossana Castrellon said in Panama City.
Even with the deal, the U.S. military doesn't have the manpower to guard all the world's waters, shipping experts said.
"If they want to be the policeman of the high seas, they can be," Osler said of the United States. "But even they haven't got the reach."