An American sentenced to two and a half years in Thai prison for translating a banned biography about the country's king and posting the content online has been freed by a royal pardon, the US Embassy said.

Joe Gordon, who was sentenced in December for translating excerpts of the book The King Never Smiles into Thai, was released from jail on Tuesday night. No reason was given for the pardon, but US officials have pressed Thai authorities to release the Thai-born American.

Gordon had posted online links to the book on Bhumibol Adulyadej several years ago while living in the US state of Colorado. He was detained in May last year during a visit to Thailand, where he had returned for medical treatement.

After being repeatedly denied bail, Gordon pleaded guilty in October in hopes of obtaining a lenient sentence.  

Thailand’s so-called lese majeste laws are some of the harshest in the world. They mandate that people found guilty of defaming the monarchy - including the king, the queen and the heir to the throne - face between three to 15 years behind bars.

Gordon's case has raised questions about the applicability of Thai law to acts committed by foreigners outside Thailand.

Source: Agencies