Letters were sent to Supreme Commander General Tanasak Patimapragorn, Army Commander General Prayuth Chan-ocha, Navy chief Admiral Narong Pipatanasai and Air Force Chief Marshal Prajin Juntong.
The letters were sent on behalf of the group’s leader, former supreme commander General Saiyud Kerdphol.
In the letters, the group said the military should not take sides in politics but should perform its duty lawfully and protect the country, religion and the monarchy.
Group member Chaiwat Sinsuwong said General Saiyud was afraid the prolonged conflict may soon deteriorate to the point where people with differing opinions clash. Chaiwat said Saiyud believed the Constitutional Court and heads of the armed forces could convince His Majesty the King to intervene.