Three helicopters were sent to the Banthad mountain range as police in four provinces hunt for escaped prisoner Chaowalit Thongduang following a clash on Wednesday.

Chaowalit, alias Sia Paeng Nanod, managed to flee after he was involved in the shootout with police on Wednesday in the mountains of Trang province. He and his armed men reportedly fled towards the eastern side of the mountain range.

Chaowalit, 37, was in prison for attempted murder. He fled from Maharat Nakhon Si Thammarat Hospital on Oct 22. He had been taken there for dental treatment and was admitted after collapsing, claiming he had severe leg pains. Despite being restrained to the bed and wearing leg chains, he escaped overnight.

Seven people were arrested for allegedly aiding in the escape of Chaowalit, and three warders faced arrest warrants in connection with his escape.

Police said the prisoner was believed to be hiding in the mountain range and they wanted him to quickly surrender.

The prisoner managed to escape because a dog at his temporary shelter barked when it saw police approaching on Wednesday, said police.

Police said Chaowalit opened fire first when he saw police approaching his hideout. Both sides exchanged fire before the prisoner fled.

A search of the shelter found a power generator, suggesting that Chaowalit had been well-prepared for his escape.

Police said the prisoner and his men were armed with weapons and more than 600 rounds of ammunition.