Burma's military government has been accused of sanctioning the use of rape as a weapon against its opponents.
The Burmese military are accused of intimidation by rape
The Women's League of Burma says despite denials by the government, sexual violence by the armed forces remains prevalent in many areas.
"The military, mostly high-ranking officers, continued to use rape as a weapon to subdue ethnic minorities between 2003 into 2004," it said.
It alleged the most recent attack was on a girl of 12 and two other women.
It said they were working in a field on 31 July this year when they were sexually assaulted by soldiers.
The Women's League of Burma (WLB), an umbrella organisation for groups of different ethnic origin, released its report, entitled System of Impunity, at United Nations offices in Bangkok, Thailand.
It contains claims of gang rape, rape and murder and
Of 26 women allegedly attacked, most were under 18, and 17 of them were raped
by senior officers, it said.
WLB spokeswoman Hseng Nong said it was not possible to find out exactly how many rapes had taken place, but said those recorded were just "the tip of the iceberg".
She said rape was officially sanctioned in an attempt to suppress ethnic minorities and their campaigns for independence and democracy.
The government in Rangoon has previously dismissed accusations of state-sanctioned rape.
The regime in Burma - officially known as Myanmar - has been regularly criticised over human rights by foreign governments since the military seized power in a 1962 coup.
However, the WLB said countries near Burma must stop co-operating with the regime and push it to accept democratic reform.
Continued co-operation was "placing the lives
of women and girls in Burma at risk", it said.