Thailand administered the states as Syburi (ไทรบุรี), Palit (ปะลิส), Kalantan (กลันตัน) and Trangkanu (ตรังกานู) provinces[2] from 18 October 1943 until the surrender of the Japanese at the end of the war.

On 14 December 1941, General Plaek Phibunsongkhram, then Prime Minister of Thailand, signed a secret agreement with the Japanese Empire and committed the Thai armed forces to participate in the planned Burma Campaign.

After occupation on 20 August 1943, an agreement on the surrender of the four states was signed in Bangkok, between Phibunsongkhram and the Japanese ambassador, Teiji Tonbukami.

On the occasion, Prime Minister Phibunsongkhram declared that the citizens of the annexed states were to be granted equal treatment to the inhabitants of other parts of Thailand.

The Japanese also had the full control of the telegraph, post and telephone services over the nominally Thai territories.