The three dead men were identified as 1st Lt Kritsana Yaphila, SgtMaj1st Class Konganun Boonaram, and Sgt Pichit Wongbor.
SgtMaj3rdClass Sitthichai Waicharoen was wounded and rushed to hospital in Aranyaprathet.
The three dead were killed Tuesday afternoon when Lt Kritsana led a seven soldier patrol to clear anti-tank landmines in Sa Kaew’s Klonghad district.
The cause of their deaths is under investigation and the area, located near the Thai-Cambodian border, is off-limits to the public for safety.
The landmines were planted in the 1970s and 1980s during the Cambodian wars.