BANGKOK, May 14 (Xinhua) -- A driver from Thailand Post, Thailand's national mailing service company, on early Tuesday was arrested in southern Thailand's Songkla for allegedly smuggling 13 illegal migrants, according to Thai police.

Police stopped a mail truck with Bangkok license plate from Thailand Post traveling in Songkla on Monday night, finding 13 Hindu men from Myanmar and their belongings in the back of the truck.

All the 13 were undocumented migrants. Police said the driver, 34, confessed that he was paid to collect the migrants from the Myanmar border in western Thailand's Kanchanaburi Province and transport them to the south.

Police said the driver had thought that using a mail truck would be less noticeable than a pickup. He was charged with assisting illegal entry into the kingdom. Investigators said an additional charge of human trafficking may be filed if further evidence arises, according to local media reports.

Thailand Post released a statement on Tuesday, saying it has expelled the driver for "serious legal and disciplinary violations" and offered full cooperation with the police investigation.

Thailand has been making efforts in cracking down on human traffickers. Human trafficking in the country is rampant in recent years, with thousands of migrants from Thailand's neighboring countries sold as slave labors.