PHNOM PENH (Reuters) - A top judge at a U.N.-backed war crimes tribunal in Cambodia on Monday criticized Thailand and Vietnam for refusing to provide evidence in the trials of Khmer Rouge leaders accused of atrocities during the 1970s "killing fields" era.
Mark Harmon, an international judge in the hybrid U.N.-Cambodian court, said he had written numerous letters to the governments of Thailand and Vietnam since 2013 asking for access to evidence that could "determine the truth", but neither country had responded.
The tribunal has delivered verdicts against only three former Khmer Rouge since it was set up almost a decade ago and it has been fraught with problems, from funding shortages to allegations of political interference to limit the scope of investigations.
"Both governments have failed to produce relevant documents that could assist with the investigations," Harmon said in a statement.
It was unclear what investigators are seeking to obtain from the Thai and Vietnamese authorities, and court spokesman Lars Olsen did not provide specific details.
Vietnam invaded Cambodia in 1979, toppling the Khmer Rouge from power. Thailand received an influx of tens of thousands of people fleeing Pol Pot's ultra-Maoist regime.
(Reporting by Prak Chan Thul; Editing by Martin Petty and Jeremy Laurence)