BANGKOK -- Thailand's anti-government People' s Alliance for Democracy (PAD) leader Chamlong Srimuang said on Monday protestors' march to seal off different locations in Bangkok on Monday is simply a prelude, as the group planned more intense coordinated protests on Tuesday and vowed to topple the government by Wednesday.

An anti-government protester waves a Thai national flag during a rally at the new government offices in Bangkok's Don Mueang (Muang) airport November 24, 2008. Thousands of anti-government protesters blockaded Thailand's parliament on Monday, forcing it to postpone an important legislative session, the latest twist to a six-month campaign to unseat the elected administration. [Agencies]

On Monday, key PAD leaders declared victory after their mass protests at Parliament prompted the cancellation of Monday's joint session of the House of Representatives and Senate.

According to the state-run Thai News Agency, police arrested six men dressed as PAD protestors, who allegedly hijacked a Bangkok Mass Transit Authority bus and drove it to the PAD protest site to be used as a road blockade.

The protestors also marched to seize the Chart Thai Party Headquarters and Finance Ministry and later changed their target to the temporary seat of government at Don Mueang Airport.

The PAD protestors seized the rooftop of the terminal building and announced its victory. The protestors also booed and attacked Deputy Metropolitan Police Chief Police Col Patchara Boonyasit, while he was walking to the Government's temporary office.

The protestors planned to camp out at Don Mueang airport Monday night while more supporters would join the group on Tuesday morning. Scores of police were on standby to prevent a possible break-in by the demonstrators.

The group also announced it would rally at Suvarnabhumi Airport on Wednesday morning to protest against Prime Minister Somchai Wongsawat from landing on his return to Thailand after attending the Asia Pacific Economic Cooperation (APEC) Summit in Peru.

The Thai government, the opposition, House Speaker and the senate president jointly agreed to hold an extraordinary parliamentary session on December 8 and 9 and would confer only on drafted international conventions and treaties to be inked at the Association of Southeast Asian Nations (ASEAN) summit in the northern province of Chiang Mai in December.