Anyone who drove by the Pentagon last weekend should have realized what was coming, even though President Bush's announcement of a military response to Iraq's invasion of Kuwait still was hours away.

With the president's plans wrapped in secrecy, there, for all to see, were thousands of cars crammed into the Pentagon's parking lots. On a Sunday.

"Not exactly a dead giveaway, but pretty close," one Pentagon official said. "When we're in a crisis, there really aren't any weekends for a lot of people."

For hundreds of Defense personnel assigned to monitor conditions in the Middle East, it has been a tense, draining week marked by 12-hour shifts, takeout meals and long lines at the Defense Mapping Agency's office in the Pentagon basement, where detailed maps of the Middle East and Saudi Arabia are distributed.

And as more than 50,000 U.S. troops begin to take up station in Saudi Arabia, the anxieties being felt at the Pentagon also were evident at military installations throughout the Washington area, particularly at Andrews Air Force Base.

At Andrews, dozens of families gathered at the base's recreation center Thursday night in what observers described as a tearful farewell to Air Force personnel believed to be participating in the massive airlift of troops to Saudi Arabia.

"I don't remember seeing anything like it," said one Air Force wife, who said her best friend's husband was among those saying goodbye to his family. "Everyone was crying. They're all so nervous about this."

Air Force and Defense Department officials will not comment on whether any of the 19,000 personnel on active duty at Andrews are being deployed, but several people who were at the recreation center Thursday said the personnel were being readied for action. Andrews is home for the 76th Airlift Division and the 89th Military Airlift Wing.

Members of the Defense Department's crisis team have spent much of the week in command centers on the second and third floors of the Pentagon, where the aromas of microwaved popcorn and delivered pizza are known as signs of a crisis.

The command center is occupied by hundreds of people from all four branches of the military, and decisions made there are acted on by Army, Navy, Air Force and Marine teams in other areas of the giant building.

Pentagon sources said the number of troops being sent to the Middle East -- described by officials as the largest U.S. military action since the Vietnam War -- has brought an intensity to the building not evident during other missions in recent years.

"This ain't Grenada, and it ain't Panama," one Pentagon source said. "There obviously is a lot more to this than was involved in those operations . . . . People here are professionals, and they just turn it up a notch during a" crisis.

The Defense Mapping Agency brought in several cases of maps of the Middle East and Saudi Arabia, and has been distributing them to Pentagon workers nearly as quickly as the maps arrive.

Military police units from Fort Belvoir saw action in Panama, but it is unlikely anyone stationed there will see action in the Middle East. Nevertheless, electrical engineering units at Belvoir have been dispatched to other East Coast installations to fill in for personnel being sent to Saudi Arabia, and the crisis is foremost on the minds of people stationed at the Fairfax County installation.

"Everybody's fighting each other for newspapers every morning," spokesman Ned Christiensen said.

Little activity was reported at Bolling Air Force Base in the District, but tensions are increased there as well.

"People are watching and waiting . . . . It's quiet, but there's a little different feeling in the air," said Gracie Aguayo, whose husband, Master Sgt. Richard Aguayo, is assigned to the ground radio communications unit on the base.

Retired Air Force Master Sgt. Ralph Anonsen, who was stationed at Andrews and still lives near the base, said he noticed a different mood during visits there last week. "Everyone -- families included -- is on edge. It comes with the territory."