The report by the Washington-based Refugees International Group (RI), based on interviews with women on the Thai-Myanmar border, suggested that the use of rape by Myanmar's armed forces was more widespread than first reported last year.

RI documented 43 rapes among women from the Karen, Karenni, Mon, Tavoyan and Shan ethnic groups and found some 75 percent of women interviewed reported knowing someone who had been raped.

"Rape is widespread and committed with impunity, both by officers and lower ranking soldiers. The culture of impunity contributes to an atmosphere in which rape is permissible," RI spokeswoman Veronika Martin said.

But the junta said in a statement Sunday that while rape cases may have occurred in the country, rape was not being used as a weapon of war.

"Isolated rape cases may have happened in certain areas as is happening in many other countries around the world," the junta's statement said.

"But 'systematically using rape as a weapon of war' is just too ridiculous and these organisations that are putting out such preposterous allegations need to be reminded that the Myanmar Defence Forces also comprises ethnic Kayin, Shan, Kayah, Mon and various other national races," it said.

"The government of Myanmar thinks that it is regretful to learn that certain individuals or organisations who may have good intentions are misled by those who wish to keep Myanmar unstable and fractured by creating misunderstanding and sowing seeds of mistrust among its national races," it added.

Allegations that Myanmar's Tatmadaw, or armed forces, used rape as a war weapon first arose last May in a report called "Licence to Rape" by two Thai-based Shan rights groups.

The report documented 625 sex attacks on Shan women and girls by Myanmar soldiers, mostly between 1996 and 2001, and drew international outrage. The junta has repeatedly denied and fiercely condemned the allegations.

In December the US State Department said that the US consulate in the northern city of Chiang Mai had found evidence supporting the accusations made by the rights groups.

It also repeated the allegations in a report released last week, which again drew sharp denials from the junta.

SPACE.WIRE