MEXICO CITY — Human rights activists accused Mexico’s military and police Wednesday of engaging in widespread torture, including the use of cattle prods and waterboarding, in President Felipe Calderon’s U.S.-backed war against crime mafias and drug cartels.In a highly critical report, the international group Human Rights Watch said it found credible evidence that “strongly suggests” the participation of Mexican security forces in more than 170 cases of torture, 39 “disappearances” and 24 extrajudicial killings in five Mexican states since Calderon began his military-led assault against the powerful crime syndicates in late 2006.The group said Calderon’s deployment on the streets of 50,000 troops, alongside thousands of federal police, many schooled by U.S. trainers, has done little to reduce the soaring violence, which has left more 46,000 dead. Instead, the mass deployment “resulted in a dramatic increase in grave human rights violations, virtually none of which appear to be adequately investigated,” according to the 214-page report, based on 200 interviews with officials, witnesses and alleged victims and on documents obtained through public information requests.The report was presented to Calderon on Wednesday in a meeting with Human Rights Watch directors. According to a statement from the president’s office, Calderon repeated that criminals represent the main threat to human rights in Mexico. “It is they who by crimes such as homicide, kidnapping and extortion are systematically violating the fundamental rights of the citizens and their families,” Calderon said. Jose Miguel Vivanco of Human Rights Watch said the two-hour meeting was a “little tense” but proved “surprisingly constructive,” with the president agreeing to examine the cases of abuse in the report and search for remedies.In all five states surveyed, Human Rights Watch investigators said, they found evidence that security forces systematically use torture to obtain confessions or information about cartels. Typically the alleged torture took place while the detainee was at a military base or police station. The alleged methods included beatings, mock executions, threats of rape, electric shocks and asphyxiation with plastic bags.“They pulled down my pants and underwear and left me naked from the waist down,” Nallely Thamara Lara Sosa, of Villahermosa, Tabasco, told the human rights investigators. “The man who was interrogating me stopped right in front of me and said, “Little Tamara, here’s when everything starts to change, now we’re going to give you love and affection because here you’re going to have many friends — they’re lining up for you.”According to the report, Marcelo Laguarda Davila was arbitrarily detained, threatened and beaten by investigative judicial police in Monterrey, Nuevo Leon, in April 2010, who accused him of killing a fellow student. “They took a cloth and they wrapped it around my head except for my nose,” Laguard is quoted in the report as saying. “Later I learned that this was what they called ‘the mummy.’ They left me like this and began to do the thing with the water again, but this time the water came in directly through my nose. They repeated this three times. That’s when I said, ‘That’s it, I’ll confess to whatever you want.’ ”The human rights activists stressed that Mexico’s military justice system should be reformed and jurisdiction transferred to civilian courts. Until last week, only 15 soldiers have been prosecuted and the process and hearings are mostly closed to outside scrutiny. In the five states studied by Human Rights Watch — Baja California, Chihuahua, Guerrero, Nuevo Leon, and Tabasco — military prosecutors have opened 1,615 investigations into rights violations since 2007. Not a single soldier in those investigations have been convicted. Last week, according to Mexico’s military, 14 soldiers were convicted and sentenced to prison in the fatal shooting of two women and three children whose vehicle failed to stop at an army checkpoint in the state of Sinaloa in 2007. A commanding officer received a 40-year sentence. A judge gave 12 enlisted soldiers 16-year sentences. The verdicts were announced in a press release a week after they were handed down. The military did not identify the personnel by name.