BOMB SHAKES CIVILIANS : AMERICANS TROUBLED BY SAUDI TENSIONS.

Byline: Steven Erlanger The New York Times

When the enormous bomb went off Tuesday at about 10 p.m., killing 19 U.S. servicemen, Ruth Rosser was making dessert for her husband, Tom. He had worked late at the Saudi company that employs him and provides his housing, in a foreigners' compound called Al Rushaid Village No. 3, less than half a mile northeast of the explosion.

``There was a big boom, a tremendous, indescribable sound, and glass was coming down like rain - we could hear it coming down,'' said Rosser, 62, still full of wonder.

``It's amazing no one here was hurt,'' she said. ``But it makes me much more unsettled. The American Consulate puts out warnings, but you think it won't happen here, it won't happen to me.

``In the shops,'' she continued carefully, choosing her words, ``you wonder which Saudis are like us and think like us, and which ones want more of this.''

But the Rossers intend to stay here - where the job and pay are excellent, amenities superb and European vacations common - ``unless we're ordered to leave, or there are a couple more bombs near us,'' she said.

Some of the 35,000 or so civilian Americans living in Saudi Arabia - 20,000 of them around Dhahran - are more jittery than the Rossers, especially families with children.

This is the largest group of civilian Americans living abroad anywhere, in this country built on oil money, where 12 million Saudis have imported 4.5 million foreigners to work for them. The Americans are skilled managers, doctors, nurses, scientists and computer experts who help run large companies for Saudi owners.

They come because of the pay and benefits. As one American said, ``No one stays here, not even the Saudis, for the sunsets.''

But beginning with a deadly bomb in Riyadh in November and now with this explosion, more Americans are thinking about how much longer they will stay.

``This changes things,'' said Paul, a 50-year-old banker here who spoke on condition that his surname not be used. ``Of course we're targets. It's easier to focus discontent on outsiders first, and once we're gone, they'll have to face it themselves.''

One reason there is less open anxiety, the Americans say, is that most wives and children are away for their long summer vacation.

Many Americans here say that in the last few months, they have noticed a significant increase in formality, distance and even hostility toward them among Saudi shopkeepers, especially toward Western women shopping together, even if they are very conservatively dressed, as they must be in Saudi society.

Dianne Steen has lived in Saudi Arabia for 19 years with her husband, who works for Aramco, the huge oil company that employs thousands of Americans, and her three children were all born here. ``There's a lot more hostility toward Westerners now,'' she said, describing how, two months ago, she and a small group of women, all wearing hats and loose, long clothing, were not served at a shop in Thuqbah, the old section of Al Khobar.

Later, she said, in nearby Dammam, the first five shopkeepers along the main row of shops ``wouldn't even acknowledge us, even though we spoke in Arabic.'' She paused. ``That really hurt my feelings. I never, ever had that.''

Steen thinks the change, based in an increasingly open religious conservatism, has political roots. ``Some of it is having to straddle the fence,'' she said. ``They don't know which way the wind is going to blow. If there's a coup and the king is thrown out, they might suffer for having served Western women.''

She described numerous run-ins she and friends have had with the Mutawwi, the religious police, who roam Saudi Arabia looking for violations of cultural and religious standards, including inappropriate dress, restaurants or shops open during the period for prayer five times a day, women smoking in public, women driving automobiles, women in public with men not their husbands or brothers, and even women who catch men's eyes.

American women have been briefly detained, for instance, for riding in the front seats of taxis next to a male driver, or for wearing tight blue jeans in public.

Some American women, like Ann Nahikian, 37, who has been here a few months after living two years in Kuwait, choose to wear the traditional Saudi abaya, or black shawl, in public, to avoid problems.

``It's their custom, and I don't care,'' she said. ``It's a minor thing to me. I have a lot of freedom inside the compound.''

Others, like Steen, dress conservatively but refuse to wear the abaya. ``It's a measure of oppression to me,'' Steen said. ``When I came here 19 years ago, the king said Western women were not required to wear it.''

But she noted that in the more conservative capital, Riyadh, ``you better wear an abaya - it's really serious there.''

All the Americans interviewed live in company compounds, walled to keep Western mores inside, hidden from the society at large. They are really villages, with gardens, pools, tennis courts, gyms and sometimes shops. They also have careful security, with visitors checked by guards.

Behind the walls, Westerners act and dress much as they please, wearing shorts or even bikinis at the pool, and it is common knowledge that inside these walls alcohol, though banned, is available.

Aramco has a series of such compounds, its largest housing thousands of foreigners, including those from Muslim countries, and providing nearly every service. But even in the Aramco compound now, Steen said, women must be careful how they dress to go to the compound post office.

In Al Bustan Village, with 220 houses, the streets have names like Fig, Mimosa and Ash. There are many activities for women and children, she said, from social and card clubs to classes and volunteer work. Local schools end with the ninth grade, and children go abroad for secondary school, usually to American boarding schools, tuition paid by the company.

Only a few women are allowed to work, usually as teachers, nurses and doctors, though some work on the compound or with the small U.S. Consulate, and Steen founded her own pre-school.

Non-Muslim religious services are banned, and whether or not underground Christian services take place is a topic no one wants to discuss. One American described a friend who asked for a cleric just before dying. The family found one who was willing, so long as his involvement was secret: He was smuggled into the hospital.