PDRC secretary general Suthep and PDRC protesters joined the allied groups of the Network of Students and People for the Reform of Thailand (NSPRT) and the People's Democratic Force to Overthrow Thaksinism (PEFOT) at Government House for the second day.
He earlier said that the protesters would occupy the area in order to prevent Ms Yingluck from working at Government House after the Centre for Maintaining Peace and Order (CMPO) announced its intention to retake the five rally sites including the Government House.
Mr Suthep admonished the protesters not to carry any weapons and to not resist if the police crack down on them, but instead sitting down to chant or perform prayers.
Metropolitan police deputy commander Pol Gen Vorapong Chewpreecha said the police would use 15,000 personnel in their operation to retake the protest sites while 10,000 police are prepared to backup the operation.
The police successfully regained the Energy Ministry compound and removed the protest stage at the PTT state petroleum company headquarters.