The main goal of the informal meeting -- which follows up on similar gatherings held in Madrid in June and in Brisbane, Australia in July -- is to convince other countries to join the Proliferation Security Initiative (PSI).

The US-led forum aims to halt the air and sea transfer of nuclear, chemical and biological weapons, their components and the missiles to carry them by using existing laws and international treaties.

So far, the group comprises Australia, Britain, France, Germany, Italy, Japan, the Netherlands, Poland, Portugal, Spain and the United States.

The main targets of the fledgling 11-member effort are what Washington calls "rogue states", with Iran, Libya and North Korea leading the most-wanted list.

US President George W. Bush launched the non-proliferation initiative in May during a visit to the Polish city of Krakow, where he called for a ban on suspicious cargos on planes and trains designed to halt the spread of weapons.

The multinational initiative is aimed at "making the fight against proliferation more effective within the framework of existing international law", French diplomats said.

The primary targets are ships transporting weapons components, which are difficult to intercept without the permission of the country in which they are registered, they explained.

Experts will seek to "make life more difficult for ships with suspicious cargo" by getting permission from coastal states and countries that issue so-called "flags of convenience" to authorize at-sea interceptions, they added.

In December, the Spanish navy -- mobilized at the request of the United States -- stopped and searched an unflagged vessel found to be carrying 15 North Korean Scud missiles to Yemen, but US forces had no legal right to seize the cargo as the ship was intercepted in international waters.

According to international maritime law, the only case in which a country can stop a ship on the high seas is if authorities suspect trafficking in slaves -- a clause dating back to 1815 that is still in effect.

On Wednesday, experts from the 11 countries, notably intelligence specialists, will meet behind closed doors in the French capital. A plenary session will follow on Thursday.

The US delegation to the Paris talks is headed by Under Secretary of State for Arms Control and International Security John Bolton.

Among those countries cited as possible new members of the proliferation initiative are Canada, China, Indonesia, Malaysia, Norway, the Philippines, Russia and Thailand, diplomats said.

WAR.WIRE