LONDON (AP) _ Amnesty International on Friday accused state security agents in more than 40 nations of ''barbaric'' treatment of women prisoners.

''Rape is sometimes the torture method of choice simply because the social stigma in many cultures virtually guarantees that women won't talk about it afterwards,'' the organization said in a report.

The London-based human rights organization issued the report Friday to coincide with International Women's Day. It was submitted to the United Nations Commission on the Status of Women to draw attention to women's rights in general.

Amnesty urged, among other things, that governments crack down on rape and sexual abuse by security force interrogators and release women detained simply because of their family connections.

In one case, the widow of a Moroccan general linked to a 1972 coup attempt, Fatima Oufkir, has been in jail without charge with her six children for nearly 18 years, said Amnesty. Reports in Morocco this week said the Oufkir family was just freed.

The report cited cases of well-known professional women who have been detained or killed for their political beliefs and also focused on the plight of peasant women in Peru or India.

The well-known women mentioned in the report included opposition leader Aung San Suu Kyi in Burma, who has been under house arrest since 1989, and South African black lawyer Victoria Mxenge. She was shot dead in 1985 and there were allegations of government complicity.

''Young and old women are raped by prison guards, pregnant women are beaten and others are used to get at their husbands or brothers,'' the 56-page report said.

Rape in custody occurs in many countries, it said.

The organization did not say in its international reports whether it believed one country was most guilty of abuse against women. Long sections of the report are devoted to descriptions of rapes by soldiers during anti- insurgency operations in Peru and by police in India, Pakistan and Burma.

In El Salvador, the right-wing government has used rape as a form of torture to extract information, the report said. It quoted Maria Juana Medina, arrested in September 1989 after her trade unionist daughter vanished, as saying she was summoned alone for interrogation, ordered to strip naked and then raped.

Other nations cited included Syria, Chad, Mauritania, Guatemala, Philippines, Turkey, Chile, Ethiopia and Iran.

''Governments will often exploit a woman's family connections to break her or her relatives,'' said the report.

''More than 70 Syrian women have been detained since 1987 because of the political activities of their husbands and sons; a gun was held to the head of a two-year-old child in Guatemala to force the mother to deliver a warning to her activist brother.''

Most of the countries cited are Third World nations.

Amnesty International, which opposes capital punishment in all cases, cited the United States for having 30 women under such sentences.