A 3-year-old Northwest Washington girl was killed yesterday in a rare and unusual accident when her clothing apparently got caught in an escalator at the Minnesota Avenue Metro station and she was strangled.

The girl was on a shopping trip with her grandmother when the accident occurred about 5 p.m. at the Orange Line station in the 4000 block of Minnesota Avenue NE, according to a police investigator.

A D.C. fire official said he believed that that nylon drawstrings used to tighten the hood of the girl's ski jacket snagged in the escalator. Other investigators said they thought it might have been the girl's scarf or sleeve that became entangled in the bottom step of a down escalator.

Described by a D.C. homicide detective as a "freak accident," the death at the station in Far Northeast was the first to involve an escalator since the Metro system opened, a Metro spokeswoman said. An official of an escalator company said he had not heard of such an accident in 20 years.

The girl, whose identity was withheld pending notification of her parents, was going downtown so her grandmother could buy her roller skates when the accident occurred, a police officer said. The grandmother's name was also withheld.

Exactly how the girl's clothing became caught was not immediately clear. A fire official who went to the scene said he believed she must have fallen.

One investigator said the grandmother tried to free the girl. Rescue workers said later that the incident left the woman hysterical.

According to Sgt. J.T. McCann of the D.C. police homicide unit, a passenger at the station notified station attendants, who switched off the escalator and summoned a D.C. fire department ambulance.

Rescue workers said they found the girl lying face down on the lowest step of the escalator. She was pinned so tightly against the tread that at one time it was believed her arm was caught, one witness said.

According to rescuers, the girl was held in such a way that she could not be freed by cutting away her clothing. They said it took 20 minutes to release her by removing the bottom step of the escalator.

The station remained open. A small crowd watched quietly.

D.C. firefighter Titus Nelson said he tried to locate the girl's pulse. "There was none," he said. Nelson administered oxygen.

The girl was taken to D.C. General Hospital where doctors used mechanical equipment to try to support her heart and lungs. Authorities said she died about 6:05 p.m.

A hospital spokesman listed the cause of death as strangulation.

No figures were available last night on the frequency of such accidents nationwide. They were believed to be exceedingly rare.

Police and rescue personnel interviewed last night said they could not remember another such death in the District.

Ronald Boice, Washington regional director of the Westinghouse Elevator Co. said he had not heard of a fatality on an escalator in his 20 years with the company.

Detectives said they were told, however, that from time to time articles of clothing become stuck in escalators here, and that they are removed without serious injury.

Homicide detective McCann said police were not certain which article of of the girl's clothing got caught yesterday. He said he expected that a determination would be made during an autopsy today.