The movements include the battle staff of Camp Pendleton's 1st Marine Expeditionary Force.

Although no final decision has been made, Rumsfeld is expected to give the go-ahead soon for smallpox inoculations, according to a senior defense official who discussed the matter on condition of anonymity.

Rumsfeld's spokeswoman, Victoria Clarke, said vaccination program is under consideration, but she would not discuss details. If it goes ahead, Clarke said it would reflect Rumsfeld's push to provide every available form of protection for troops who might be exposed to chemical or germ weapons – including those who might fight in Iraq.

"The threat to those in the military is very real," she said.

Hundreds of thousands of U.S. troops have received vaccines to protect them against anthrax, and after a long pause in that inoculation program, the pace of vaccinations was accelerated last month, officials said.

The Pentagon has taken numerous steps in recent weeks to position U.S. forces so as to reduce the time required to launch an attack on Iraq, should President Bush decide that force is required to disarm Saddam Hussein.

In the latest such move, the Pentagon ordered the battle staffs of the Army's V Corps, with headquarters at Heidelberg, Germany, and the Marine Corps' 1st Marine Expeditionary Force, based at Camp Pendleton, Calif., to go to Kuwait, according to two officials familiar with the planning. Several thousand U.S. ground forces already are in Kuwait, mostly at Camp Doha.

Those moves, first reported in Saturday's Washington Post, strongly suggest that Rumsfeld is putting in place the battle planners and command staffs that would be called on to spearhead a land assault on Iraq.

The V Corps is the Army's only corps headquarters based outside the United States, and its combat units – including the 1st Armored Division and the 1st Infantry Division – are specifically trained for fighting in Europe or the Middle East. The V Corps is commanded by Lt. Gen. William Wallace and has 41,000 troops.

V Corps recently redesigned its main command post, making it completely modular and more mobile.

The battle staff of U.S. Central Command, which would have overall responsibility for war in Iraq, is planning to move to an air base in Qatar next month from its headquarters in Tampa, Fla. The move is billed as an exercise, but officials say the staff – including the commanding general, Gen. Tommy Franks – may remain in Qatar in anticipation of a presidential decision to go to war.

Franks already has his naval command staff in Bahrain and his air command staff in Saudi Arabia.

One of the key worries about building up forces in the vicinity of Iraq is the possibility that Saddam could launch a pre-emptive strike using biological or chemical weapons. Thus the Pentagon is considering additional protections, such as the vaccine for the virus that causes smallpox, as first reported in Saturday's New York Times.

U.S. officials suspect that Iraq has strains of the smallpox virus that could be used against U.S. troops, although the Iraqi government insists it destroyed all its biological weapons after the 1991 Gulf War.

The Health and Human Services Department recently informed the Pentagon that it would make about 1 million doses of the smallpox vaccine available for inoculating troops. The White House has not yet decided whether civilians will be offered the smallpox vaccine.

Vaccinations for troops could begin as early as November, officials said. First to receive it would be those whom the Pentagon calls "first responders," troops responsible for responding to domestic disasters such as a bioweapons attack. They include medical specialists. Next to get it probably would be troops in combat units designated to deploy first in a major military crisis abroad, such as the Army's airborne infantry.

As many as 500,000 troops might eventually be inoculated, according to another senior defense official. Of the 1.4 million men and women in the active-duty military, fewer than half have ever received the smallpox vaccine, the official said.

On the Net:

Defense Department at www.defenselink.mil

1st Marine Expeditionary Force at www.cpp.usmc.mil/imef/

Army V Corps at www.vcorps.army.mil/www/default.htm