Soldiers from the Third Infantry Battalion of the 23rd Infantry Regiment raised the national flag and sang the national anthem at Prasat Khana in Surin to honour three battalion troops killed during an operation to recapture the site from Cambodian forces.
The Internal Security Operations Command (ISOC) said in a Facebook post at 6.40am on Sunday that the battalion held a ceremony at noon on Saturday at the historical site.
ISOC said Prasat Khana was the first area recaptured from Cambodian forces when the second round of border clashes erupted on December 8, but it was the last site where the Army raised the national flag.
ISOC said the ceremony was meant to signal that Thai soldiers would remain at the site and would not allow anyone to violate Thai sovereignty again.