Thai Prime Minister Yingluck Shinawatra has expanded a special security law to cover more of Bangkok after opposition led protesters broke into key ministries in a bid to topple the government.
Appearing on national TV late Monday, the prime minister said the Internal Security Act would now apply to all parts of the capital and some surrounding areas.
The measure, which already was in effect in some downtown districts, allows police to close roads, impose curfews and carry out searches.
Earlier Monday, thousands of anti-government protesters seized the Finance Ministry and marched on a dozen other government facilities.
More than 1,000 protesters swarmed into Finance Ministry buildings, while others forced their way into the Foreign Ministry compound, but did not entered any of the buildings.
Police, who have not tried to remove the protesters, said about 30,000 marched on at least 13 government facilities across the capital.
Protesters led by the main opposition party want the prime minister to resign, accusing her of being a puppet for her exiled brother, ousted prime minister Thaksin Shinawatra.
Thousands of pro-government protesters held their own rally at a Bangkok stadium and vowed not to leave until the opposition calls off its demonstration. Many Thais fear violent clashes could erupt between the two groups.
Mass protests were triggered several weeks ago by an amnesty bill that would have allowed Thaksin Shinawatra to return home and avoid a two-year jail term for corruption.
The amnesty bill was rejected by the Senate, but opposition-led protests have continued. Tens of thousands rallied against the government on Sunday.