Although Vietnamese Catholics in Northern Virginia were truimphant recently when they established the first Vietnamese-run Catholic Church in the country, a series of vandalism incidents has turned their joy to despair.

The Rev. Tran Duy Nhat, pastor of the Church of the Blessed Vietnamese Martyrs in Annandale, said the harassment began in early September at the church's formal dedication ceremonies.

"All during the service [a group of young adults] drove around the parking lot yelling things" in mock Chinese, said Nhat.

Since that time, church members said, groups of teens and young adults, usually in a red pickup truck or gold Chevrolet, have vandalized church property and caused disturbances during the daily evening masses.

Dr. Bui H. Thu, chairman of the parish council, said the teen-agers stole the battery from a parishioner's car during a service, painted obscentities on the church steps, and pelted Nhat's car with eggs.

Nhat said he was awakened at the neighboring church rectory one-night when he heard a crash and saw a red pickup truck speeding away after smashing the side of his car.

Nhat said that when he tried to call the police, he discovered his telephone wires had been cut.

"I don't know why they do this to us," said Nhat. "We worked very hard to fix up the church and now they do this. I hope they don't have anything against us."

Most recently, after several church members spent the weekend installing a heavy wooden fence to help protect the church, Nhat rose Monday morning to discover a 30-foot section of the fence missing and the post holes filled in with gravel.

"It must have been a big boy who took it," said Bui. "I helped put in the fence and it was very heavy, I don't know how they got it out, the posts were two feet in the ground."

Nhat said he reported the three worst instances to the police, but is puzzled why the attacks have continued. Following the theft of the fence, Fairfax County police officer Donald Hall told church members to place telephone posts with stakes along the curbs to keep out the vandals' cars.

Fairfax County police Lt. Thomas Bowen said police files show only one reported instance of vandalism at the church. "Before they [the Vietnamese] moved in, that church had the normal amount of vandalism," Bowen said. "It doesn't appear that they have any more vandalism now than other similar institutions. I don't think any of it is directed at the church or the people."

Bui blames the disturbances and vandalism on a group of teen-agers and young adults who used to use the church property as a meeting place before the Vietnamese moved in. "Maybe they got mad because we occupy the building now and they can't have parties there anymore," he said.