Bangkok - Thai police on Sunday arrested Chamlong Srimuang, one of nine leaders of the protest movement that has occupied government headquarters for the past 41 days, to face treason charges.

Chamlong was arrested shortly after he left Government House and cast his vote in Bangkok's gubernatorial election.

"I will repay my debt to the nation," Chamlong wrote in a letter he had left among his supporters among the People Alliance for Democracy (PAD) that stormed Government House with thousands of followers on August 26 and have occupied the seat of the executive power since.

Chamlong, a former army major-general whose colourful career has included a stint as governor of Bangkok and leading mass protests in the capital that have helped overthrow two former prime ministers including Suchinda Kraprayun in 1992 and Thaksin Shinawatra in 2006, was the second PAD leader to be arrested this month.

Chaiwat Sinsuwong, another senior PAD figure, was arrested Friday.

Both men face charges of sedition for leading thousands of followers to occupy the grounds on August 26. The executive body has been without offices for the past month and a half.

Treason carries the maximum penalty of death in Thailand.

The PAD is a loose coalition of groups staunchly opposed to the return to power of former prime minister Thaksin and his political cronies.

Thaksin, a billionaire former telecommunication tycoon who won unprecedented mass support during his two-term premiership by introducing populist policies aimed at the poor, was outed by a military coup on September 19, 2006.

The PAD played a key role in organizing mass demonstrations against Thaksin in 2006 that culminated in his downfall. Chamlong organized similar protests to unseat former prime minister General Suchinda in May, 1992.

That protest ended in bloodshed when the army cracked down on the demonstrators, leaving more than 100 dead or missing.

The PAD movement took to the streets again in May this year when it became obvious that the government of former prime minister Samak Sundaravej was pushing for constitutional amendments that might have led to a political comeback of Thaksin and 110 of his close political allies who have been banned from politics for five years.

Samak, a close political ally of Thaksin's, lost his job last month after the Constitution Court found him guilty of moonlighting on the premiership by hosting television cooking shows.

He has been replaced by Somchai Wongsawat, Thaksin's brother-in-law. Both Samak and Somchai are members of the People Power Party that won the December 23, 2007, general election on a pro-Thaksin campaign platform.

Unlike Samak, Prime Minister Somchai has adopted a conciliatory approach to the PAD.

It was Samak who persuaded police to charge the PAD leaders with treason for seizing Government House. The charges have been highly criticized for being too extreme. (dpa)