A State Department investigation has corroborated reports earlier this year that Burmese military officials have systematically raped ethnic minority women and girls, according to a recently declassified copy of the investigation report.

The Burmese government has denounced as a fabrication reports of mass rapes by the military. In June, the Thailand-based Shan Human Rights Foundation and the Shan Women's Action Network detailed rapes involving at least 625 girls and women by Burmese army troops in Shan state, the largest of the seven ethnic minority states in Burma, also known as Myanmar.

The report by the Thailand-based groups concluded that the Burmese military, as part of its campaign to bring ethnic areas under its control, officially condones rape as a "weapon of war" against civilians. At the time, the State Department issued a statement saying it was appalled by the report and urged an investigation by the Burmese government, a step the regime initially resisted.

Washington then sent a State Department investigator to the Burma border in August to make its own assessment. "We were able to locate many victims and record chilling new stories of rape and other atrocities in just three days," the investigator reported. All of the victims had been gang-raped by Burmese soldiers within the past five years, including a 13-year-old girl who had been raped two months earlier.

"The older women sobbed violently as they recalled horrific incidents of their own rapes as well as brutal rapes, torture and execution of family members," the State Department report said. "Most of these women had just recently arrived in Thailand and were thin, lethargic, despondent and had no belongings or hope for the future."

The investigator, to try to assess the credibility of the original report by the Thailand-based organizations, also met with one woman whose case was documented in the report. The woman, who had been gang-raped when she was seven months pregnant, "told us her story in generally the same terms as those recorded in the report."

The State Department probe has helped spur the U.S. government to seek an international investigation of the rape charges, a State Department official said. The State Department investigation "collaborates that the rapes have been going on and likely on a widespread basis," the official said.

"The international community cannot stand by and allow these heinous crimes by the Tatmadaw [the Burmese military] to continue with impunity," the department report concluded. "We should continue to pressure the regime to end this violence and punish the perpetrators."

Last month, Assistant Secretary of State James A. Kelly blasted the regime's handling of the rape allegations, including an effort to claim that a field trip into the region by the International Committee of the Red Cross represented an investigation -- which the Red Cross denies.

"For a regime spokesman to deny categorically all charges of rape without any investigation does more than strain credulity," Kelly said. The approach by the government "devalues the representations of the [regime] to the point that even tentative concrete steps -- such as the eventual, reluctant, acknowledgement by the government that rapes had indeed been committed by soldiers -- are submerged in the outrage over the indefensible."

Human rights groups allege that the military regime has forced village elders in Shan state to sign petitions that the rapes did not occur.

In November, Paulo Sergio Pinheiro, the United Nations special rapporteur on human rights in Burma, reported to the U.N. General Assembly that the regime had given him "detailed briefings" on its investigations into the rape charges. He said he sought to explain that probes undertaken by the military "lacked the independence required to be convincing and credible" and that an international probe, either under U.N. control or with U.N. technical assistance, was required to address the charges.

"We remain skeptical that any proper investigation into this issue can take place inside Burma while the military regime remains in power," said Mo Lao of the Shan Women's Action Network, which co-wrote the original rape report.