The US Embassy in Cambodia on Thursday claimed on its official Facebook page that there was no evidence the US government was involved in the 1970 Cambodian coup d’etat that precipitated much of the unrest that ravaged the country in the years after.

“We would like to highlight that the US was not involved in the coup leading to Lon Nol coming to power. Up to now, there has not been any evidence proving the US was involved."

“Instead, there is a lot of evidence proving that the Chinese government actively supported the Khmer Rouge regime from 1975 to 1979 and in eras after that,” read its statement written in Khmer.

The coup, which occurred on March 18, 1970, saw Prince Norodom Sihanouk overthrown with Prime Minister Lon Nol taking his place.

Despite denials by the US government, many believe it orchestrated the overthrow. It is generally considered a major turning point in the Cambodian civil war and a major contributor to the rise of the genocidal Khmer Rouge regime.

The embassy’s message came in response to claims by Cambodian Facebook users implicating the US government in the events of 1970.

One user named Mony Chan wrote: “If there was no US support for Lon Nol to stage a coup to topple Norodom Sihanouk in March 1970, there would be no Khmer Rouge forces to bring Cambodians to the killing fields.

“In short, the US, in large part, was the root cause and was a founding contributor leading to the Khmer Rouge regime and the killing fields of Cambodia.”

Another Facebook user named Bong Kla suggested the US provided vital weapons and backing, asking the US embassy whether “Lon Nol used Chinese weapons?”

Mony Chan’s comments echoed those of Prime Minister Hun Sen in a speech early last month marking the 40th anniversary of Cambodia’s January 7 liberation from the Khmer Rouge.

The prime minister claimed that Cambodia’s five-year civil war from 1970 and the horrific four-year period under the Khmer Rouge between 1975 and 1979 was a direct consequence of the toppling of Sihanouk’s Sangkum Reastr Niyum regime in 1970.

The comments also come at a time of growing tensions between Cambodia and Western nations, with the US and the EU both threatening punitive economic measures against Hun Sen’s government over what critics claim is a decline in democracy and human rights in the Kingdom in recent years.

Read more: China’s embassy mocks US over Lon Nol claims

Thursday’s message from the US Embassy also honoured the more than two million Cambodians who were killed during the Khmer Rouge regime.

On November 16 last year, the Extraordinary Chambers in the Courts of Cambodia (ECCC) sentenced former Khmer Rouge leaders Nuon Chea and Khieu Samphan to life for genocide, crimes against humanity and grave breaches of the 1949 Geneva Convention.

In reference to the verdicts, the embassy said: “The verdicts of the [ECCC] is the first recognition that the Khmer Rouge regime committed genocide as specified under international law.

“This verdict should bring hope for those seeking truth and responsibility in Cambodia, as well as in other countries, who are trying to reconcile with this past brutal act."

“It should be a strong warning to governments and groups committing brutal acts or eliminating people’s voice showing justice can prevail when we all jointly seek transparency, truth and responsibility.”

Accompanying its message, the US embassy also posted a series of photos, one of which depicts Khmer Rouge leader Pol Pot and the then Vice Chairman of the Central Committee of the Communist Party of China, Wang Dongxing, together.

Government spokesman Phay Siphan responded on Thursday by criticising the US Embassy for posting the photo, accusing it of a diversion campaign that attempted to place blame on China for the genocide.

He continued by denying Cambodia was beholden to Chinese influence and called for the US to respect Cambodian sovereignty.

“We do not bow to any country. We would like the US to respect the sovereignty and independence of Cambodia. Don’t smear our country by saying that Cambodia bows to any country . . . Cambodia just has a goal to protect peace not only at home but also in the region,” he said.

Kin Phea, the director-general of the Institute of International Relations at the Royal Academy of Cambodia, said the legacy of the US involvement in the events of 1970 were still there to see today.

“Do we not see the US bomb craters? The legacy of unexploded ordnance is their war legacy. Can they claim [culpability for the Khmer Rouge] belongs to China more than the US?” he asked.