BANGKOK, THAILAND - The leader of an offshoot of Thailand's "Red Shirt" movement was indicted Thursday on charges of insulting the monarchy with a speech given two years ago, a court official said.

Surachai Danwattananusorn, who faces 15 years in prison if convicted by the Criminal Court, is accused of criticising the royal family when he addressed supporters of his "Red Siam" group on December 15, 2008 in a Bangkok park.

The 68-year-old denies the charges, which were made under Thailand's strict lese majeste rules.

Anti-government "Red Shirts", whose April and May rallies descended into violent clashes between troops and protesters that left over 90 people dead, distance themselves from Red Siam because of its radical leftwing politics.

Surachai, a former member of the now-defunct Communist Party of Thailand, surrendered to police in March 10, 2009.

King Bhumibol Adulyadej, the world's longest reigning monarch, is revered as a demi-god by many Thais and any discussion of the royal family is an extremely sensitive topic in politically turbulent Thailand. --AFP