LOS ANGELES, JULY 10 -- A Salvadoran woman living in Los Angeles and active against U.S policy in El Salvador told police she was abducted and tortured Tuesday night.

Leaders of the Committee in Solidarity with the People of El Salvador (CISPES), a group opposed to U.S. policy in Central America, said the kidnaping of Yanira Corea, 24, was politically motivated and may mark the first physical attack in the United States of the sort used by right-wing death squads in Central America.

Lt. John Borunda of the Los Angeles Police Department said the case is being investigated as a kidnaping and rape. He said that in a brief initial interview with a female investigator, Corea did not mention a political motivation but reported her conversations with her abductors fully today in a more thorough police interview.

A CISPES spokeswoman said Corea had been terrified during the first interview and feared reprisals if she mentioned politics.

Hugh Byrne, CISPES Western regional director, said Corea was taken at knife point from in front of CISPES headquarters here by men whom she identified by their accents as two Salvadorans and a Honduran or Nicaraguan.

Byrne said the men blindfolded Corea, shoved her into a van and questioned her about her political activities in Los Angeles.

When she refused to give information, Byrne said, they tortured her and sexually assaulted her. Corea, who is employed here but does not have legal U.S. residence, had come to the CISPES office to help plan a fund-raising event by a Salvadoran women's group in which she is active, Byrne said.

A statement by her mother said that Corea had been followed recently and that her car once had been run off the road by two men in another car. CISPES leaders said the men appeared to know Corea's name, asked specifically about Byrne's activities and knew that Corea has a 3-year-old son.

Craig L. Stephens, a physician who examined her Wednesday, said Corea "had multiple contusions to her head, back and abdomen, cuts on her hands and tongue, cigarette burns on her hands and evidenced of rape with a foreign object." Stephens said the injuries resembled those on other victims who say they have been kidnaped in El Salvador. He said he made those examinations in connection in asylum application cases.

CISPES leaders initially did not give the woman's last name, and she did not appear at a noon news conference at the group's Los Angeles regional headquarters. Later, they provided her full identity. She gave interviews to three reporters but declined a request for a Washington Post interview.

Byrne released a list of recent incidents -- including vandalism of cars and offices -- directed at the organization's members. He said the Reagan administration encouraged such activity "by doing nothing about it."

CISPES supports a political solution to the civil war in El Salvador and opposes U.S. support for the Salvadoran army in its fight against Marxist insurgents. Byrne noted that a former FBI informer, Frank Varelli, has testified that he infiltrated and reported on a CISPES organization in Dallas.