The allegations are contained in a 12-page report the London-based group turned over to a special Mexican federal prosecutor's office for crimes against women, which it asked to take over the case.
“The state of Mexico promised there would not be impunity, but what we've found up until now is that the necessary steps haven't been taken; in fact, it's completely the opposite,” organization investigator Rupert Knox told The Associated Press in a telephone interview from London on the eve of the report Wednesday night.
Knox said Amnesty fears the cases might be forgotten with Mexico's transition to a new government on Dec. 1, and that the organization will ask to discuss the situation with aides to President-elect Felipe Calderon.
Seven women claimed they were raped and another 16 said they were sexually abused after being taken into custody by police who retook control of the town of San Salvador Atenco, 25 kilometers (15 miles) northeast of Mexico City, to end violent protests in early May.
The protests began with demonstrators kidnapping and beating six policemen, one brutally, after authorities tried to prevent flower vendors from setting up stands in a nearby city.
Police responded with rage the next day: Television images showed angry officers repeatedly clubbing helpless detainees in the town. More than 200 people were taken into custody.
Mexico's National Human Rights Commission filed complaints with the prosecutor for Mexico State, where San Salvador Atenco is located, and President Vicente Fox's office said the case should be thoroughly investigated and that any officers found responsible for sexual abuse or any other crime should be punished.
In June, Mexico State prosecutor Abel Villicana Estrada said he would press charges against 23 police officers for using excessive force. It was not immediately clear what the status of those cases were.
In addition, four police officers were fired and five others suspended for 90 days for tolerating the use of excessive force – but apparently none has been tried or convicted for rape or sexual abuse.
Mexico State Police Chief Wilfrido Robledo repeatedly has denied the allegations, initially saying they were part of a strategy by detainees' lawyers to make police look bad. In an interview last month with a Mexican magazine, he insisted the women had made up the charges.
Sections of the Amnesty report deal with the alleged lack of attention authorities paid to women who made the complaints.
“When I arrive (at the authorities' offices), the doctor doesn't want to certify that I've been raped,” said one alleged victim whose testimony was included in the report. “It seems unfair that they don't believe me, that someone could think I made this up.”
The report claims that by not attending the complaints, authorities have violated a law in the state of Mexico against torture as well as several international accords Mexico signed guaranteeing human rights and the prevention of abuse against women.
“According to international law, the rape of a woman or child who is in the custody of an agent of the state always constitutes torture, for which the state is directly responsible,” the report said, concluding, “It's time to review the methods, training and tactics of the public security forces in situations of public disturbances or protests to ensure that they are in line with international human rights norms.”