Updated

The military planned Tuesday to deploy live anti-aircraft missiles to launchers stationed around Washington for a training exercise, calling it a "prudent precaution" on the eve of the first anniversary of the terrorist attack on the Pentagon.

Defense Secretary Donald H. Rumsfeld ordered the missiles taken to the launchers, where they could be quickly loaded and fired if needed. The Bush administration raised the nation's terrorism alert level Tuesday to its second-highest level, code orange.

"This is not a response to any specific threat but is a prudent precaution to increase the radar and air defense posture in the national capital region," a Pentagon statement said.

The original exercise was to involve testing of air defense systems around Washington. It included radar systems, military aircraft and Stinger anti-aircraft missiles, some in their portable form and some in batteries mounted on Humvees.

One of the launchers, called an Avenger, was parked Tuesday several hundred yards from the Pentagon. Three soldiers and a civilian could be seen gathered around the battery.

Military officials would not say where else in the Washington area the missile launchers were in place. The exercise does not include Patriot missiles, which can shoot down both jet airplanes and incoming missiles.

Heat-seeking Stinger missiles are designed to shoot down low-flying airplanes and helicopters as well as cruise missiles.

The military raised security to the highest level, "delta," at the base in Bahrain that is home to the U.S. Navy's 5th Fleet, Pentagon officials said Tuesday. Other U.S. bases overseen by Central Command, which covers the Persian Gulf, the Horn of Africa and Central Asia, boosted security to the second-highest level, "charlie," officials said.

Those increased security measures were because of the same threats that prompted the change in the national alert level, according to a Pentagon official who spoke on condition of anonymity.

Security has been tightened at the Pentagon and military bases worldwide in the days leading to the anniversary of the Sept. 11 terror attacks. The military resumed 24-hour fighter-jet patrols Friday over Washington and New York City.