The Organisation for the Prohibition of Chemical Weapons (OPCW) wrapped up its investigation into chemical substances left behind by US bombing during the Vietnam War this weekend, according to government newswire AKP.

The Cambodian government first appealed to the international body in October, as tensions were escalating with the US.

The Kingdom accused it of not taking responsibility for its war legacy, while the US Embassy accused Cambodia of politicising the issue by trying to discredit the superpower over its purported support of the now-dissolved opposition Cambodia National Rescue Party.

Chey Son, secretary-general of Cambodia’s National Authority for Chemical Weapons, said the OPCW will test the substances in the Netherlands, but said he did not know when results would be available.

“Cambodia is not the boss of them. We are asking for help from them; [we] can’t order them to send the report this day or that day,” he said.

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Son also declined to comment on what the substances might be until the results were delivered to the government.

The OPCW has repeatedly declined to comment, citing “strict confidentiality”. On Wednesday, they said the results would not be made public.

“There are 29 sites of suspected chemical weapons found in Svay Rieng, two in Tboung Khmum, and ten in Mondulkiri,” the AKP article said, although Son said there are likely locations in other provinces that weren’t investigated.