The Defence Volunteers wear green uniforms similar to the army's and drive army-style vehicles.
While the "forces" in Patong refused to speak with anyone who inquired what they were doing, or to allow any photography, another group in Phuket Town told The Phuket News that they had been ordered to set up road blocks to carry out random drug tests.
Last night's exercise is part of the ongoing anti-narcotics campaign by Deputy Prime Minister Chalerm Yubamrung, who has set a target of 400,000 arrests of drug dealers and users nationwide.