The exercises started after comanders received "intelligence" that a merchant ship, which embarked from Turkey's Mediterranean port of Antalya, was transporting chemical weapons to a hostile country.

US, Turkish, French and Porteguese warships raced into the open sea and patrol aircraft took off to monitor the ship. Two Turkish F-4 fighter jets performed low-altitude flights over the vessel.

A Turkish helicopter from a warship chased a civilian helicopter that was apparently trying to take cargo from the suspected vessel and forced it to land at Antalya.

The allied warships then surrounded the vessel off Antalya.

Turkish commandoes slid down ropes from a helicopter onto the vessel and US commandos arrived from the sea on a motorboat, securing the ship and comandeering it to Antalya.

The exercises were part of the Proliferation Security Initiative (PSI), a three-year-old US-led effort that aims to stop shipments of biological, chemical, and nuclear weapons, missiles and goods used to produce weapons of mass destruction, to terrorists and suspect countries.

Ankara has denied media reports that the drills were aimed at its eastern neighbor Iran, which the US claims is developing atomic weapons under the cover of a nuclear energy program.

The operation was coordinated with Turkish customs officials and security forces at the port.

Under an additional scenario, experts from Turkey's atomic energy institute, clad in green protective gear, searched a truck carrying suspected nuclear materials.

Officials from 31 other countries, including Israel and several Arab nations, observed the drills, called Anatolian Sun 2006, Turkish diplomats said.

"The exercise was very useful. It will be an example for the international community," Turkish General Tuncer Erinmezler told reporters.

The first phase of the drills, which started Wednesday, consisted of a computer-simulated exercise.

Officials say such exercises are crucial to stop the spread of weapons of mass destruction.

The PIS, launched by US President George W. Bush in 2003, is supported by more than 60 nations.

It commits countries to disrupt trade in weapons of mass destruction by interdicting vessels, aircraft or other modes of transport that are suspected of carrying suspicious cargo.

Iran's neighbors, including Turkey, have come under increasing pressure to cooperate with Washington and push Tehran to give up what the United States believes is a secret nuclear weapons program.

Ankara has repeatedly urged Tehran to be more transparent about its nuclear activities and resolve the dispute through diplomatic means to avert a possible military confrontation in the region.

Related Links