The Foreign Ministry has slammed comments by Thai anti-government protest leader Suthep Thaugsuban accusing Cambodian forces of possibly having killed a senior protest figure last week as “foolish”, with analysts saying the allegations are only the most recent iteration of anti-Cambodian rhetoric long used by nationalist Thai groups for political purposes.

Speaking on Sunday just hours after the fatal shooting of Sutin Tharatin, a leader of the People’s Democratic Force to Overthrow Thaksinism, an ally of Suthep’s People’s Democratic Reform Committee (PDRC), Suthep opined that the shooting could have been carried out by a Cambodian “special warfare” unit brought in from Cambodia to attack protesters. Yesterday, Foreign Ministry spokesman Koy Koung rejected the claims.

“I categorically reject such claims. This is a silly claim by Suthep Thaugsuban.… Cambodian people in Thailand just only work at factories or companies to earn money [to send] back home,” he said. “We always advise them to stay far from any assembly or any protest.”

Earlier last week, a senior officer in the Thai navy told The Nation newspaper that Cambodians were being ferried into Thailand to attack anti-government protesters.

Naval Special Warfare Commander Winai Klom-in said that 10 vans of Cambodians had crossed the border into Thailand last Monday but were not stopped by police.

According to Koung, those reports were officially rejected by the Thai Foreign Ministry in communications with the Cambodian embassy in Bangkok. The Thai Foreign Ministry did not respond to a request for comment yesterday.

Exiled former Thai premier Thaksin Shinawatra – who is widely believed to still pull the strings in his sister Yingluck’s government and who is the key target of current protests – is close with Prime Minister Hun Sen, which is one reason Cambodia is often targeted by conservatives in Thailand, analysts say.

“The anti-Cambodian sentiments among the protesters are unsurprising. They date back to the Preah Vihear saga in 2008 and have continued since then, reinforced by the close relationship between the Thaksin camp and the Cambodian leadership,” said Thitinan Pongsudhirak, a political scientist at Chulalongkorn University.

In an interview with the Bangkok Post published on Monday, Suthep claimed that Thaksin would soon be arriving in Cambodia “to give direct orders”.

“We are seriously worried about violent attacks by foreign armed men. I coped with them in 2010.… However, I am glad the military are alert. Those who are patriots will not let any party use armed foreign forces to kill Thai people,” he said.

Koung dismissed the allegation that Thaksin was coming to Cambodia as “another fantasy claim”.

“Mr Suthep just says rubbish things in [recent] days,” he said, adding that Suthep had a history of trying to create rifts between Thailand and Cambodia, including as a member of the conservative government that ruled as border skirmishes erupted in 2011.

Phil Robertson, deputy Asia director at Human Rights Watch, said that Cambodian workers in Thailand could be put at risk as a result of Suthep’s rhetoric.

“Suthep’s allegation that Cambodians might have been behind the killing of Suthin Tharatin is inflammatory and lacks any sort of evidence.… He’s engaged in a dangerous game of whipping up nationalist hatred against Cambodia to further his political allegations against Thaksin,” he said.

“The threat against migrant workers from Suthep’s rhetoric is real. Those Cambodian migrant workers who are in areas where the PDRC are particularly active – such as Thailand’s southern provinces – are vulnerable to violence by vigilantes, increased abuses in sweeps by authorities looking for Cambodian ‘terrorists’, and other possible abuses.”

But Thitinan, the Thai political analyst, said that unless “serious evidence” emerged to back up claims that Cambodians had been hired to work for Thaksin, “we will probably not see enough xenophobic traction to endanger Cambodians who live in Thailand”.