Sixteen Thai nationals were arrested on Thursday for illegally crossing the Thai-Myanmar border in northwestern Thailand, a government official said.

The 16 males were spotted and arrested by authorities after they had crossed Moei river on the Thai-Myanmar border at night and slipped into the Thai territory in Phop Phra district of Tak province, said chief district officer Sompong Fungthaweewong.

The Thais admitted to having been hired as workers at a casino in Myanmar's Myawaddy township across the border from Thailand's Mae Sot district, just north of Phop Phra district, and decided to flee the pandemic in the neighboring country, Sompong said.

They all have taken a test for COVID-19 at a detention center in Tak immediately following their arrest, he said.

The Thai authorities have temporarily shut down border checkpoints to stem possible cross-border transmission of virus and have frequently conducted border patrols to keep out any trespassers.