Armed men in civilian clothes dragged at least a dozen students from shacks in a slum near San Salvador's opulent Sheraton Hotel late this morning, tied them up, threw them on the floor of two vans and took them away, according to residents of the neighborhood.

The families of the abducted young people, who ranged in age from 15 to 19, say they are afraid that like many similar cases here in the last few years these abductions were for the purpose of murdering suspected political subversives.

"What have they done with my son? What have they done?" one mother moaned.

Other members of the community appeared stunned by the action. As they talked to a reporter they glanced nervously up the steep steps carved unto the hillside that led to the street above.

When the armed men arrived, one woman said, "We asked them to identify themselves, and they answered with a machine-gun in our face."

Another woman whose son was taken away this morning said that the armed men accused the young men and women of having burned two small buses at nearby Jose Artiga Circle on Friday.

"One boy was studying for a physics test," said a nearly panicked woman from the neighborhood. "They said he was studying to make bombs."

Residents also said that when guerrillas carry out actions in the area they come down off the slopes of nearby San Salvador Volcano. Sometimes they pass along the dusty trails of the slum, but no one in these impoverished homes admits to knowing or wanting to know what they are doing.

Salvadoran National Police patrol the quiet, upper-class streets that overlook the cardboard-and-mud huts of the slum, but none were in sight when about eight men in three vehicles arrived in the neighborhood at 11 a.m., according to residents.

An official of the Salvadoran National Police, reached by telephone, said that a patrol was sent out to investigate the matter after a reporter called on the basis of a rumor shortly before noon. The patrol found nothing, he said.

But the mothers of two of the abducted students and other members of the community said this afternoon that the authorities they have contacted, including the National Police, say they know nothing about the case.

"They told me they would investigate the case, but not until tomorrow," said Maria Leonor Martinez after returning from police headquarters in an attempt to find out what happened to her son, 18-year-old Ivan Enrique Portillo.

Hermenia Mendez was walking with her 15-year-old daughter, Alva Luz, from a nearby grocery to their open-air shack when two vans and a car stopped near them. The men took the girl away.

"We've gone to the police, to the National Guard, and they have not given us any news of her," said the mother, her voice steady at first, then breaking in sobs.

"They tied up the kids and threw them on the floors of the vans and took them away," said one woman. "We don't know who did it. We don't know why. We just don't know."