The incident occurred at about 4:30am at the Indian Oriental Kitchen on Rat-U-Thit 200 Pi Rd, Patong Police confirmed.
Patong Police were alerted by the police radio centre and dispatched officers to the scene, where the front of the restaurant had been damaged, with shattered glass and items scattered across the premises.
Rescue workers had already transported the injured to Patong Hospital before police arrived. The injured were later identified as Paveen Negi, Umed Kumar and Ram Chandar.
Initial enquiries found that the explosion occurred as staff were closing the shop and carrying out cleaning duties. Police said a gas leak was heard moments before the blast.
Acting Patong Police Superintendent Pol Col Korakrit Khanthakrue confirmed that officers had inspected the scene and visited the injured men at Patong Hospital.
“The Forensic Science Division has been notified to jointly inspect the scene to determine the exact cause of the explosion,” he said.
Investigating officer Pol Lt Tharnnathon Meechina added that police will interview the injured and question witnesses and related parties as part of the investigation.
No arrests have been made and no suspects have been identified at this stage, Patong Police confirmed.