DOHA, Qatar, Dec. 7 -- A major American military headquarters is fully operational at a base near here, U.S. officials said today, for possible use in a war with Iraq.

Gen. Tommy R. Franks, who would take charge of the war, presided over the opening of a two-day walk-through in advance of computerized war games, designated Internal Look, scheduled to begin Monday. About 200 U.S. staff members participated today, along with military observers from Britain and Australia, identified by U.S. officials as part of "the coalition." In a statement to the group, Franks stressed the virtue of being ready for anything.

"Even the best plans change once action starts," he said. "And we need to be flexible and agile enough to meet any contingencies."

The headquarters provides command and control for U.S. land, sea and air forces in the Middle East, Central Asia and East Africa. The debut of the Central Command Deployable Headquarters coincides with a tense diplomatic drama being played out in Baghdad, where today Iraqi officials delivered a 12,000-page declaration to the United Nations reiterating Baghdad´s denials regarding chemical, biological and nuclear weapons programs.

President Bush has expressed intense skepticism that Iraq would offer full disclosure of its programs and has reserved the option of invading the country to overthrow President Saddam Hussein. Bush´s military tools are almost in place: In recent days, independent observers in the United States have estimated that forces could be ready to invade Iraq by the end of the month.

Activation of the headquarters is only the latest element in a military force that has gradually grown in size and spread throughout the region. On Thursday, the aircraft carrier Harry S. Truman left Virginia for the Middle East at the head of a multi-ship battle group. It will join three other battle groups, led by the carriers Abraham Lincoln, George Washington and Constellation, that are already in place.

For several weeks, thousands of soldiers have been practicing warfare in Kuwait, and military equipment has poured into the oil-rich country that Iraq invaded a dozen years ago. The United States is pressing Turkey, site of a major air base, to serve as a staging ground for U.S. troops. Jet bombers are based in Kuwait, Saudi Arabia, Oman, Turkey, on the Indian Ocean island of Diego Garcia and in Qatar, a flat, dusty peninsula 300 miles south of Iraq.

About 55,000 U.S. soldiers, sailors and Air Force personnel are within striking distance of Iraq, among them 15,000 "trigger-ready" ground troops, U.S. officials said. Defense Secretary Donald H. Rumsfeld has tried to keep secret the numbers and whereabouts of the forces. "We´ve been moving forces around the world," he said at a news conference last week. "We´ve got a somewhat higher presence in the Central Command area today than we did last week or the week before or the week before that." The Central Command area encompasses 25 countries from Central Asia through the Middle East into East Africa.

Today, Franks, dressed in shades of sand desert camouflage, was surrounded by the equipment necessary to launch warfare. According to U.S. officials here, Franks can perform the same command tasks in Qatar as from MacDill Air Force Base in Tampa, the Central Command´s home. After the Internal Look exercise ends, the modular buildings and equipment will remain in place in case there is a real war.

Internal Look will center on a "fictitious but realistic" combat scenario in the region, U.S. officials said. The exercise will "test our ability to communicate with the modern battlefield," said a senior Central Command official. The week-long evaluation will present commanders with a variety of plots: invasion, resistance, attacks and counterattacks involving land, sea and air forces. No soldiers, tanks, planes or ships will move around; everything will be done by computer simulation. Maps, graphs and tables will let commanders know the location of friendly and enemy forces, as well as their activities, casualties and need for ammunition, supplies and air or artillery strikes, according to published reports.

Central Command officials declined to confirm the published reports. "Secrecy saves lives and increases the commander´s options," said Jim Wilkinson, director of strategic communications. The two-day exercise launched today, designated Rock Drill, centers on cataloguing the forces and arms available for the war games. Officials here likened Rock Drill to the kind of war-gaming that used to take place on tables, with pieces moved by hand.

Franks labored in a gymnasium at the 262-acre al-Sayliyah military base, just a few miles from Doha, the capital of Qatar, a sheikdom rich with oil and natural gas. (© 2002 The Washington Post Company 12/08/02)