Mr Chamlong was arrested as he went to vote in city mayoral elections
Police in Thailand say they have arrested a key organiser of mass anti-government protests in Bangkok.
Chamlong Srimuang was detained after leaving the prime ministerial compound, where he and thousands of supporters have been barricaded since late August.
He is one of nine protest leaders accused of illegal assembly and inciting unrest.
Protesters demand the resignation of the government, which they say is a proxy for ousted PM Thaksin Shinawatra.
Mr Chamlong was arrested as he arrived at a polling station to cast his vote in Bangkok's mayoral elections.
Another protest organiser, Chaiwat Sinsuwong, was detained on Friday as he left the compound.
A police spokesman told the Associated Press that the authorities were preparing to arrest all the protest leaders at the appropriate time and place.
Demonstrators from the People's Alliance for Democracy (PAD) have been occupying key government buildings in Bangkok for more than two months.
They have vowed to remain in place until their demands for a government independent of Mr Thaksin are met.
Last month, Mr Thakin's brother-in-law, Somchai Wongsawat, won a majority parliamentary vote to become the country's new prime minister after a court forced his predecessor, Samak Sundaravej, to step down.
Chamlong Srimuang 
Police in Thailand have announced the arrest of Chamlong Srimuang, a retired general and former Bangkok mayor who is one of the leaders of protests against the current government. Chamlong and other protesters who have occupied government buildings for several months accuse the incumbent government of acting as proxy for deposed prime minister Thaksin Shinawatra.

Chamlong is the second of the People's Alliance for Democracy (PAD - Thai: พันธมิตรประชาชนเพื่อประชาธิปไตย) protest leaders to be arrested; Chaiwat Sinuwong was arrested on Friday as he left the occupied prime minister's compound. Former mayor, Chamlong had today left the security of the protest site to vote in the city's elections.

Protests have been ongoing, led to a September, 2006 military coup, and have centred around corruption allegations initially championed by Sondhi Limthongkul against Thaksin Shinawatra who the coup deposed and left in exile for in excess of a year. Following the dissolution of Thaksin's Thai Rak Thai party, and an October, 2006 election, the protesters have focused on removing what they perceive as Thaksin's ongoing influence on the country's government. In June then-PM Samak Sundaravej and his cabinet narrowly survived a no-confidence vote. Last month saw him replaced with the incumbent, Somchai Wongsawat following a court decision. Somchai was appointed as the result of a parliamentary vote, protesters are particularly incensed at this as he is former PM Thaksin's brother-in-law.

Charges of insurrection, illegal assembly, and inciting unrest have been brought against nine of the protest leaders, including Chamlong; police have vowed to arrest all the protest leaders although there are no plans to employ force to carry this out. The charge of insurrection in Thailand is the equivalent of treason, the sentence can be life imprisonment or even the death penalty.

Government proposals for the deputy prime minister, Chavalit Yongchaiyudh, to negotiate with the PAD have been scuppered by the two arrests. According to the Thai News Agency, the leaders of the PAD state that the negotiations are unlikely to take place now. The arrests were described as indicating the government was not sincere and the PAD will "not hold talks with irresponsible people".

The outstanding arrest warrants are for the PAD founder, Sondhi, the group's leaders and spokesman, Somsak Kosaisuk, Pibhop Dhongchai and Suriyasai Katasila, MP Somkiat Pongpaibul, and protest organisers Therdpoom Chaidee and Amorn Amornrattannond. An appeals court challenge against the arrest warrants is pending and a decision is expected Monday; if the warrants are revoked, it is expected that the Royal Thai Police will instigate a judicial process to contest this.