A press conference was also held, presided over by Lt Gen Walit Rojanapakdi, the 4th Army commander, Pol Lt Gen Panya Mamen, the 8th Provincial Police Region chief, and governors of the 14 southern provinces.
Lt Gen Walit said the weapons were seized in operations between May 29 and June 25. They include 21 rifles of various types, 150 shotguns, 399 handguns of various types, 13 hand grenades and 4,502 rounds of assorted ammunition.
The weapons had been seized from armed units in the three southern border provinces and influential persons who were involved in underground businesses. Some of them were dumped at various locations by those who illegally had then in their possession.
"The exisistence of the armed units and influential persons involving in illegal businesses is real. They were preparing to stage violent incidents. Suppression of these illegal weapons will continue," Lt Gen Walit said.
Those with information to sources of illegal weapons are urged to call the number 1111 so that the authorities can take action, he added.