Anti-government protesters had laid siege to the Agriculture, Tourism and Transport ministries, and were attempting to occupy the Interior Ministry, on Tuesday.
According to a Thai Rath report, demonstrators continued to stream into the three ministries.
Security remained stringent outside the Interior Ministry on Asadang Road in Phra Nakhon district where members of the People's Democratic Force to Overthrow Thaksinism (Pefot) had encircled the premises, blocked all entrance and exit gates and called on people working in the ministry not to cooperate with the government and to return home immediately.
Gen Preecha Iamsuphan and Somkiat Pongpaiboon, leaders of the Pefot group, asked ministry officials via speaker phone if they wanted to stand on the side of the people or the government under the Thaksin regime.
They gave officials an hour to leave the compound and go home. Anyone wanting to leave after the deadline was told they would not be allowed.
The protesters announced they would stay outside the ministry overnight and would cut off electricity and water inside this evening.
Interior permanent secretary Wiboon Sanguanpong ordered officials to stop working and go home.
The ministry deployed about 100 territorial defence volunteers to guard the premises and erected a fence of barbed wire inside and on top of the entrance and exit gates.
Protesters on Monday occupied the Finance Ministry, the Budget Bureau, the Foreign Ministry and the Public Relations Department (PRD).
Pefot members surround the Interior Ministry on Tuesday and call on people working in the ministry to leave immediately. (Photo by Pattarachai Prechapanich)