Twenty Uighurs remained at large on Monday after breaking out of their concrete cell overnight.
The illegal migrants were being held at an immigration police unit in Sadao district, near the Thai-Malaysian border.
They are among 25 Uighur people who were arrested in 2015. They were being held at the centre after their claimed nationality was not confirmed. They do not want to be sent back to China, saying they fear for their safety.
Sources said the escapees made two holes, each about 30 centimetres wide, through the wall of their cell. They broke out at about 2am on Monday.
They used blankets as ropes to lower themselves about 3 metres to the ground. They also used blankets to cover the wire around their cell and then climbed over it. Five of the migrants were unable to make it out before police noticed the escape.
Police and soldiers, assisted by sniffer dogs, were trying to track down the fugitives.
Uighurs are a Turkic ethnic group who live mainly in the Xinjiang Uighur Autonomous Region of China. They argue that they suffer widespread discrimination in China and have long been campaigning for an independent state.
