Fair Party list-MP Kannavee Suebsang is pressing the government to investigate reports of heavily armed Myanmar soldiers crossing the border into Umphang district of Tak province.
If the reports are confirmed, the the government must tell the public what happened, he said.
The two incidents led the Karen National Liberation Army (KNLA) to perceive Thailand as siding with the Myanmar military, said the opposition MP, citing exchanges on some Myanmar- and Karen-language media.
“That kind of violation of Thailand’s state sovereignty by close to 100 Myanmar soldiers is a national issue, not a border matter,” he said.
The Ministry of Defence and the Ministry of Foreign Affairs should investigate the matter and treat it as an international relations issue, he said.
Citing information from activists working in the Thai-Myanmar border area, Mr Kannavee said that between 80 and 100 armed Myanmar soldiers entered Thailand through two border villages, Ban Le Tong Khu and Ban Mo Ta Lua, on Sept 3.
The soldiers camped out in a paddy field, just a kilometre away from the nearest Thai community, while on the other side of the border, a Myanmar village was surrounded by the Karen armed guerillas, he said.
Thai villagers later alerted their village head to the presence of Myanmar soldiers on Thai soil, he said.
Thai soldiers stationed nearby refused to do anything about the invaders until a netizen posted on social media on Sept 5 about the presence of the soldiers, he said.
A source said the army’s Naresuan Task Force sent a team to negotiate with the Myanmar soldiers and the KNLA, until the KNLA agreed to stop blocking the soldiers’ way.
The Myanmar soldiers, however, still refused to leave, which prompted the Thai military to negotiate with them for a second time before the Myanmar soldiers eventually departed.
The following weekend, villagers spotted a further 10 to 20 armed Myanmar soldiers returning to Ban Le Tong Khu to buy food, which prompted more reports to the village head.
Choku Rotsirichai, the village head, reported the incident to the Thai military which sent soldiers to negotiate and ensure the soldiers’ return to their own territory, he said.