Thailand's King Bhumibol Adulyadej on Sunday approved a new interim constitution submitted to him by Thai military leaders, who staged a coup last month.
The ruling junta is to announce an interim prime minister.
The military generals who seized power in a bloodless coup on September 19 had vowed to step aside and allow a civilian government run the country. But the military will still reserve the authority to replace that government.
General Winai Phattiyakul, secretary general of the Council for Democratic Reform (CDR), said the junta would change its name to the Council for National Security from Monday to reflect a diminished role in the day-to-day governing of the country.