Nine mortar shells, believed to have been hidden during the communist insurgency four decades ago, have been found in a cave in the northeastern province of Nakhon Phanom.
Local residents contacted authorities after making the discovery in the cave in Phu Phan Noi mountain, which lies in Phuphayon national park in tambon Kanluang of Na Kae district.
Explosive ordnance disposal (EOD) officers from the 23rd Bodrer Patrol Police Division joined district officials and volunteers on a 20-kilometre trek to the scene on Saturday.
Once inside the cave they found nine Khor 81 mortar shells, each weighing about 10 kilogrammes and 30 centimetres long. All of the shells were said to be in good condition and were later destroyed.
Authorities believed the shells might have been cached for use during a battle against communist insurgents in the 1970s because Na Kae district was known to be one of their strongholds at the time.
Communist Party of Thailand (CPT) guerrillas waged a campaign against government forces from 1965 to 1980 when the government under Gen Prem Tinsulanonda offered an amnesty. The CPT ultimately abandoned the armed struggle in 1983.