Efforts by the U.S. community here to tighten security following a series of anti-NATO bombings now include instruction of American elementary school children to help protect them from terrorist attacks.

A psychologist employed by the U.S. Embassy has visited kindergarten and first- and second-grade classes at the International School of Brussels, where half of the 1,100 students are American, while a regular embassy security officer has met separately with parents to offer advice on safety.

The psychologist, Beth Huse, said she encouraged the children to "play it safe with strangers" and be wary of unknown persons who offer them rides or approach their homes. The school has received two bomb threats since September.

Huse said she did not use the word "terrorist" in her presentation, although some of the children were clearly aware of the worries of adults. "When the school steps up security, they the children want to know why," she said.

The embassy security officer also has met with parents at the Brussels American School, run by the Department of Defense, where all 300 students are American. One of the entrances to the school grounds, where a NATO clinic and recreation facility are located, has been closed off with a parked van, while the other entrance is guarded by U.S. soldiers.

The large American community in the Belgian capital, which includes NATO diplomats, military officers and executives of the dozens of American multinational firms, has been made increasingly nervous by the recent wave of terrorist attacks in Belgium and other West European countries.

Robert Franks, the embassy security officer who spoke to parents at the schools, said that in the past, Americans "found excuses" not to come to his presentations.

"Obviously now, with the increase in terrorist action, they are willing to listen," he said. The embassy "has been rather strapped recently" by requests for help to improve security, he added. "My wife now asks if I'm coming home this week, not tonight."

Franks said a frequent question he was asked was, "Am I a target?" He said he could assure most people, because they were not senior diplomats or business executives, that they did not have to worry. Nevertheless, he offered what he said was "common sense" advice: vary your routes to work and be alert to surveillance by strangers.

For the American community, two of the attacks by the Belgian group, which calls itself the Fighting Communist Cells, were particularly disturbing. The first was the bombing of an office of the American defense contractor Honeywell Inc. last October. The second was a car-bomb attack on a U.S. military administrative headquarters in a Brussels suburb Jan. 15 that slightly injured an Army guard.

After the second attack, the group said it had demonstrated that it could kill "Yankee soldiers" and warned that it did not hold human life "sacred."

Concern was also created by the sudden appearance of large vans parked around the U.S. Embassy during the third week of January. According to Brussels newspaper reports, the Belgian government had received intelligence information indicating that Islamic terrorists might attempt a suicide truck attack against the embassy. U.S. Embassy officials would not confirm the report, although they said they appreciated the Belgian assistance in protecting the embassy.

Following the Honeywell bombing, "there was quite a lot of anguish among wives of top executives," said Kathy Webster, a director of the American Women's Club in Brussels. The fear was especially pronounced if the companies of their husbands "were in any way attached to the military."

Some of the women's husbands received special safety instruction after the Honeywell bombing, such as changing the routes they took to work, she said.

The American Chamber of Commerce of Belgium held an informal meeting of representatives from U.S. firms to discuss methods of improving security. Some obvious ideas were suggested, such as registering cars in company parking lots, said chamber President John Egbers, but "otherwise, we feel kind of helpless."

"We don't know when they the terrorists will strike next," he said.

The January bombing, the first direct attack against a U.S. military target, convinced Huse that school children needed to be included in the embassy's safety programs. She said the feeling in the embassy's community liaison office where she works was, "How much closer can it get? We thought now is the time to get something going."

She said she found that some parents were considering driving their children to school because they feared that school buses were possible terrorist targets.

Robert Akers, the superintendent of the International School of Brussels, said he welcomes the embassy assistance. "There's nothing we can do" to protect the school's 45-acre open campus, he said. "We have all types of traffic coming through."