Activist groups on Thursday called on parliament to investigate whether Thai officials had conspired with the Myanmar military, which led to the intrusion of a Myanmar fighter jet on June 30.
The Democracy Group, together with the Nonthaburi New Generation Network, wanted members of parliament to find out if there was any collaboration between Thai and Myanmar officials, aimed at threatening Karen people living along the border.
On June 30, a Myanmar MiG-29 fighter jet was spotted crossing into Thailand's airspace over Phop Phra district, Tak province. The incident caused panic among locals in Ban Wao Lay Tai and Ban Wao Lay Nua villages in tambon Wao Lay, Phop Phra district.
According to the two activist groups' suspicion, the intrusion was rooted in "a shared conspiracy for ethnic annihilation" of the Karen people.
If Thailand was involved, it could be seen as a war crime, they said.
Democracy Group member and political activist Somyot Pruksakasemsuk said that Lt-Gen Apichet Suesat, commander of the Third Army Region, went to Nay Pyi Taw, the admiinistrative capital of Myanmar, to attend a border committee meeting on June 29.
"How come no one suspects anything?" the political activitist said, referring to the coincidence of Gen Apichet's visit and the intrusion.
"This action clearly shows how the Thai and Myanmar authoritarian states pose a potential threat to Asean and the rest of humanity."
Move Forward Party MP Rangsiman Rome said what is happening in Myanmar would have an adverse impact on Thailand because people living on both sides of the border were closely related.
Following the fighter jet incident, things were now getting out of hand, Mr Rangsiman said.