Published: Wednesday March 31, 2010
Stephen Rapp, the US ambassador-at-large for war crimes issues, told reporters the donation was made "in light of continued progress" with the establishment of an independent official to help monitor graft.
The UN-backed court, which finished arguments in its first trial in November, has faced controversy over allegations of government interference and claims that Cambodian staff were forced to pay kickbacks for their jobs.
"We believe that credible steps have been taken (against corruption)," Rapp said in a US embassy press conference.
"The whole world is aware that Cambodia is moving forward from a dark period of its history," he said, adding the funds would be intended for the court's second trial, of four senior regime leaders, expected to begin early next year.
Up to two million people were executed or died of starvation, disease and overwork as the 1975-79 Khmer Rouge movement emptied cities and enslaved the population on collective farms in its bid to create a communist utopia.
The long-awaited first trial heard Duch, real name Kaing Guek
Rapp told reporters he was not troubled by allegations that Cambodia's administration has attempted to interfere in the tribunal to protect former regime members who are now in government.
"From my observations, the court is able to do its work," Rapp said.
Amid repeated warnings by premier Hun Sen that further cases against the hardline regime could spark civil war, Cambodian and international prosecutors have clashed over whether the court should pursue more suspects.
The tribunal was created in 2006 after several years of haggling between Cambodia and the UN.