A "Red-Shirt" supporter of ousted Thai prime minister Thaksin Shinawatra holds a poster of him during a rally in Bangkok Oct. 17, 2009. [Xinhua]

About 6,600 security men have been deployed at the Prime Minister's Office compound and other key state buildings as they have also laid blockages and barbed-wire around the Government House.

Before today's rally, the government imposed the Internal Security Act (ISA) from Oct. 15-25 in Dusit district in order to keep peace and order at the mass rally site.

UDD core leader Jatuporn Phrompan earlier said the protestors will disperse at midnight after demanding the government to speed up legal procedure on a royal pardon for ousted former Premier Thaksin Shinawatra.

"Today, we just want to signal to the government to speed up (the royal pardon process), while we will disperse at 24.00 p.m.," said Jatuporn.

Hundreds of "Red-Shirt" supporters of ousted Thai prime minister Thaksin Shinawatra hold a rally in Bangkok Oct. 17, 2009. [Xinhua]

On August 17, the red-shirted people submitted the appeal to a representative of the Office of His Majesty's Principal Private Secretary, which was later forwarded to the government for further consideration.

Meanwhile, the UDD group plans to stage a rally at the ASEAN Summit's venues to demand the government to conduct a referendum to seek public opinion on the 1997 and 2007 constitution.

The rally at the ASEAN Summit will be peaceful and will not prolong, Arisman Pongreungrong, a UDD core leader, said at the anti-government rally site.

However, in a bid to maintain security, the Internal Security Act has been imposed by the Thai government from Oct. 12 until 27 at the venues of the Summit and related meetings.

The ISA law has prohibited any protest inside or in areas surrounding the ASEAN Summit and related venues.

The 14th ASEAN summit and its related summits in Pattaya in April were forced to cancel due to thousands of pro-Thaksin red shirt protestors stormed in the meeting venues.