The exercise, called "Millennium Challenged," is based on a real-world military threat in a country on which the military has realistic data, the officials said, without naming the country.

The forces, consisting of 13,500 men and women of the army, navy, air force and Marines, are conducting live training maneuvers at nine locations, including San Diego, southern California and Nevada, and computer simulations in 17 locations around the country.

Officials from the departments of state and energy as well as the Central Intelligence Agency (CIA) and US Agency for International Development are also taking part in the secret exercise, which began on July 24 and will last until August 15.

The exercise will not only test the effectiveness of the force, but also the progress made in transforming the force into one that can "meet the threats and the challenges of the 21st century," Secretary of Defense Donald H. Rumsfeld said after inspecting the US Joint Forces Command war-fighting center in Suffolk, Virginia.

He said the exercise is "important to future battlefield successes" because it will help strengthen coordination among the four services.

One purpose of the exercise, which was mandated by the congressand held after two years' planning, was to judge progress being made in the military's transformation into a lighter and quicker force.

(Xinhua News Agency July 30, 2002)