SINGAPORE, Jan 21 (Reuters) - Global shipping faces unprecedented threats from radicals linked to Osama bin Laden’s al Qaeda network who have been trained in suicide attacks developed by Sri Lanka’s Tiger rebels, security experts said on Tuesday.

Suicide sea bombers are the latest addition to a growing list of threats facing the global shipping industry, which is already on heightened alert as Washington and its allies prepare for a possible attack on Iraq, shipping industry officials told a conference.

The Maritime Intelligence Group, a Washington-based think tank, said members of a Southeast Asian Islamic militant group, the Jemaah Islamiah, had been trained in sea-borne guerrilla tactics developed by the Liberation Tigers of Tamil Eelam (LTTE), one of the world’s most feared rebel armies.

Jemaah Islamiah has been linked by the Singapore government to al Qaeda, blamed by Washington for the September 11, 2001 attacks on the United States.

"We know that Jemaah Islamiah has benefited from the capabilities of the LTTE," Kweilen Kimmelman, a senior analyst at the Maritime Intelligence Group, told a conference on shipping security. "They have had training in our estimation — certainly in terms of suicide diving capabilities and ramming."

"Ramming" involves loading a boat up with explosives and steering it into a target. It is one of several chilling techniques honed by the Tamil Tigers in their 19-year civil war against the Sri Lankan government.

"The threat levels are unprecedented," Kimmelman said.

Other attack methods include the use of "human torpedoes," underwater motor-propelled sleds used by divers to launch suicide attacks, along with deep-sea mines and small submarines.

"Ramming" is among the biggest worries for shippers after a small boat laden with explosives ripped through the French supertanker Limburg last October in the Gulf of Aden, killing a crewman in what Yemen called a "terrorist act."

A similar attack in the Singapore and neighboring Malacca straits, a 1,000 km (621 mile) narrow stretch of waterway that is among the world’s busiest shipping lanes and a vital lifeline between Asia and the rest of the world, could be devastating.

"Yemen now loses $3.8 billion a month, which was a significant source of its revenue, as a result of reduced traffic," she said. "A similar attack as was carried out in Yemen in the Straits of Malacca in Singapore would have catastrophic implications on the economy here."

The chief of the U.S. Coast Guard, speaking at the same conference, urged governments worldwide to implement tough new maritime regulations to prevent a seaborne catastrophe on the scale of the September 11, 2001, attacks on the United States.

"We have seized on the very difficult task of improving the security of our ships, ports and waterways against increased threat of global terrorism. This is an enormous task," said Admiral Thomas Collins.

"Clearly none of us can do it alone."

New regulations come into force next year requiring governments, port authorities and ships to implement security measures at their own level, but the shipping industry is still debating who will pay for them.

Some shippers worry that the flow of global trade will slow down once the International Code for the Security of Ships and Port Facilities (ISPS) and Amendments to the International Convention for the Safety of Life at Sea (SOLAS) come into effect from July 1, 2004.

The SOLAS amendments and the ISPS Code, adopted by the 162-member International Maritime Organization (IMO) last month, call for companies operating ships of more than 500 tonnes on international voyages to designate security officers, prepare new plans and be fitted with new security alert systems.

Ports are also called on to undergo new port facility training, undertake new security assessments, appoint security officers and prepare a security plan that meets the terms of the International Code for the Security of Ships and Port Facilities.