DHAHRAN, SAUDI ARABIA, JAN. 21 -- For John Ricciardi, the decision was made shortly before midnight -- after he spent more than two hours huddled with his wife and 13-year-old daughter in their sealed-off bathroom, gas masks strapped to their faces, listening to deafening explosions that rattled the walls of their home.

For Rita Steininger, it was made three hours later -- after the second wave of Iraqi Scud missiles was fired at this city 200 miles from the Kuwaiti border. "It's horrible," Steininger said. "We love it here. We don't want to leave our home . . . but it's a very stressful situation right now."

Ricciardi and Steininger are among hundreds of Americans living in eastern Saudi Arabia who have called the U.S. consulate in recent days and signed up for "voluntary departure" flights out of the country. About 700 Americans -- most of them the wives and children of employees of Saudi Aramco, the world's biggest oil company -- are scheduled to leave by the end of the week.

A U.S. military C-141 Starlifter flew the first group of 35 out early Sunday night and flights were continuing to take off from the vast U.S. air base here tonight and will for the next few days, a U.S. consular official said.

Eastern Saudi Arabia was the home to about 12,000 Americans before Iraq invaded Kuwait in August. The largest chunk of them lived in the sprawling, heavily guarded Saudi Aramco compound -- a suburban-like village complete with swimming pools, ball fields, a movie theater and country club.

By last week, the U.S. population had dwindled to about 7,000. But a hard core of "Aramcoms," as the Saudi Aramco employees call themselves, has fiercely resisted any talk of evacuation. Some contend that while U.S. troops are risking their lives in part to defend the Saudi oil fields, it is their patriotic duty to stay on the job.

"It may sound kind of hokey, but I feel like if the flow of oil is important to our national interests, it's important enough for me to do my part," said Michael Cox, a systems analyst who sent his wife and children home to Texas months ago.

Last weekend, after a few quiet nights with no missile attacks, many were determined to stay, convinced that Iraq's arsenal had been largely destroyed by U.S. bombers and would never threaten their homes.

But those hopes were sorely tested during more than three harrowing hours of air raid sirens, sonic booms and missile explosions Sunday night and early today. Three Scuds were fired at Dhahran about 9:50 p.m. Sunday. Three hours later, two more were fired at Dhahran and four at Riyadh. All but one were shot out of the sky by U.S. Patriot missiles and caused no reported injuries; the 10th fell into the Persian Gulf.

"I was frightened, no bones about it," said Ricciardi, the principal of a Saudi Aramco-run elementary school, who said he ran to alert his daughter when he first heard the sirens. "After that first raid, I said to my wife, 'That's it, you're getting out of here. We're not going to put up with this anymore.' "

U.S. officials continued to insist, however, that there is no reason for Americans to leave. "We don't see them {the Scuds} as a major threat," said the U.S. consular official, who spoke on the condition that he not be named. "In essence, the missiles are coming in, but they're not having any impact. We believe the area is protected."

But such reassurances do not satisfy many Americans here now. Some said today that the real damage from the missiles is the psychological toll they are taking, especially since they could carry chemical warheads. Even the mere fact that Iraq is still able to launch the rockets despite the heavy U.S. bombardment of the past week is unnerving, some Americans here said, and raises questions about what else Iraqi President Saddam Hussein may have up his sleeve.

"People are sitting around saying, 'How much more of this are we in for?' " said Kathleen Owens, wife of a Saudi Aramco manager who left Houston seven years ago to raise her family here. "What has me concerned is this guy has pretty much lived up to what he said he was going to do, and I just don't know where it's going to end."

As recently as Sunday, Owens said, she and her husband were firmly committed to staying for the "long haul." But by today, they were making contingency plans. "We might just get in our Land Rover and go off camping in the desert for a few weeks," she said. "That's our escape plan."

The uneasiness is spreading just as rapidly among other foreigners here -- Filipinos, Thais, Pakistanis and others -- as well as among the Saudis. Many shops have been shut for the past week. In a mall near here, every store front was boarded up or locked except one: the office of Saudia Airlines, which was packed with foreigners seeking to buy tickets to Riyadh so they can fly out of the country.

Khalid Duolah, 31, an unemployed Saudi welder, watched the scene somewhat helplessly. "Of course, we are all scared and everybody would like to leave," he said. "But go where? This is my home."