Thai authorities arrested Jagtar Singh, a Pakistani man convicted of terrorism charges in India, officials said on Tuesday.
Thai police arrested Singh at a house in the province of Chonburi 90 kilometres east of Bangkok.
According to Police General, Kritpongthorn Thanakornviriya, Singh, who was in Thailand under the alias Gurmeet Singh, is in custody at a local police station where he will face fines for illegal entry and stay.
He said that he would then be transferred to police headquarters in Bangkok where he is due to face extradition to India.
However, the Indian embassy in Bangkok has already requested Singh’s extradition.
The Sikh separatist militant was found guilty of a 1995 bombing that killed at least 15 people including a chief minister in the Indian state of Punjab.
He, along with two other convicts, escaped from a high security prison in 2004.