Experts, who also hailed from Britain, France, Germany, Italy, the Netherlands, Poland, Portugal and Spain, gathered behind closed doors here for what was described as a day-long "technical-political" meeting, without adopting any specific measures, Spanish diplomats said.

The forum is a first response to US President George W. Bush's call for greater international cooperation during last month's launch of a drive against weapons of mass destruction.

"The United States asked us to draw up this impromptu meeting to give a first boost to their initiative," the diplomats said.

Their talks were to include strategies for intercepting cargos suspected of containing chemical, biological or nuclear weapons, or missile components, a US State Department official who requested anonymity said earlier.

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

In December, the Spanish navy stopped and searched an unflagged vessel in the Mediterranean 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.

A senior Bush aide said in late May that the incident prompted the administration to "start thinking about ways to develop new capabilities and groups of countries willing to develop legal tools and pool resources to actually prevent proliferation from occurring."

The plan would permit searches of suspect cargo on planes and ships and the power to seize materials useful in the manufacture of weapons of mass destruction.

But the initiative is likely to face considerable hurdles, not least because it will need to deal with the prospect of searches by outside authorities inside sovereign territory.

"One of the things we need to do with the countries that are interested is to decide what authorities we need for actions inside territorial waters, inside national air space, at ports, in the air, to get things done," the official said.

WAR.WIRE