Armando Siahaan, Singapore – Western governments supported the mass murder of more than half a million alleged communist supporters in the wake of the 1965 coup, a noted historian said on Wednesday.

Speaking on the opening day of an international conference in Singapore to discuss arguably the darkest chapter in Indonesia's history, Bradley R. Simpson, an assistant professor at Princeton University and an expert on Indonesia, said that the US and British governments did everything in their power to ensure that the Indonesian army would carry out the mass killings.

Simpson, the author of "Economists with Guns: Authoritarian Development and US-Indonesian Relations, 1960-1968," said the administration of US President Lyndon Johnson initially provided expressions of political support to the Suharto regime after the coup on Sept. 30, 1965.

He said the US government then provided covert monetary assistance to the Indonesian Army, while the CIA provided the small arms from Thailand.

The US government also decided to provide limited amounts of communications equipment, medicine and a range of other items, including shoes and uniforms, he said.

"The United States was directly involved to the extent that they provided the Indonesian Armed Forces with assistance that they introduced to help facilitate the mass killings," Simpson said.

Simpson said the British government extended an emergency loan of 1 million pounds ($2 million) to Indonesia in late 1965 and promised not to attack Borneo if Indonesia withdrew soldiers engaged in a conflict with British-backed Malaysia.

But Simpson said that he found "zero evidence" that the US government masterminded the coup, in which communist-leaning founding President Sukarno was effectively replaced by Western-leaning future dictator Suharto.

"There is a lot of evidence that the US was engaged in covert operations.?.?. to provoke a clash between the Army and the PKI.?.?. to wipe them out," Simpson said, referring to the Indonesian Communist Party.

David Jenkins, former foreign editor of the Sydney Morning Herald, said that the Australian, British and US embassies were aware of the mass killings, but did not raise a single protest to the systemic slaughter launched by the Army against the PKI.

None of the embassies believed the PKI had initiated the coup. The Australians believed the coup was an internal army affair with the last-minute backing of the Communist Party, said Jenkins, basing his arguments on statements by officials. "Australia was pinning its hopes on Suharto," he said.

Jenkins said the US assessment also suggested that the coup was not run by the PKI, but that they came on board as the coup began.

Despite the embassies acknowledging that the PKI was not involved, they did nothing to protect them from the military. "The 1965-1966 Indonesian Killings Revisited" is the largest conference on the subject, which remains taboo in Indonesia.

The three-day event, held by the National University of Singapore and the Australian Research Council, involved more than 30 scholars from around the world, including Indonesia.