A Swiss man who witnessed the killing of his Italian friend by Salvadoran troops Tuesday night said today that it was "an accident" and that "I have nothing against El Salvador or the soldiers."

The comments by Claude Bernard Levanchy, who was wounded in the leg in the incident, did little to explain exactly how Vittorino Ardetto was killed.

An Armed Forces communique said yesterday that soldiers killed Ardetto after the driver of a pickup truck in which he was riding ignored a guard's order to halt and raced through a roadblock. The incident took place on the Pan-American Highway about 40 miles east of San Salvador, near a camp where Ardetto and Levanchy lived while working on a dam project.

The communique did not say whether Ardetto was killed while the pickup was driving away from the roadblock or after it had stopped. The embalmer of the body said that Ardetto had been shot in the chest.

Levanchy interviewed in his hospital bed here, declined to provide details about the incident, saying, "The world does not need to know." But he appeared not to blame the Salvadoran soldiers for what happened, saying that they bandaged his wound after the shooting.

"I knew when I came to work in El Salvador two years ago that it might be dangerous," he said.

The Italian Embassy rebuffed attempts by reporters to obtain comment. The embassy did not want to make public any details beyond those included in the Salvadoran Armed Forces communique, according to two sources familiar with the incident who requested anonymity.