A respected former prime minister was named a caretaker in the same post Wednesday in a surprise move that sidetracked a pro-military politician whose nomination had drawn sharp criticism.

Anand Panyarachun, a former diplomat and businessman who served as interim prime minister after a coup last year, was appointed to the country's highest political post by King Bhumibol Adulyadej, the constitutional monarch.Speaking to reporters at his home, Anand said he would head an interim government for four months to prepare for parliamentary elections.

Referring to recent bloody street protests over decades of military dominance of politics, Anand said: "Any society that has gone through a trauma needs to restore its balance. We have to keep in perspective our priorities: organize a free and fair election."

Political leader Somboon Rahong, held partly responsible by many Thais for the army's bloody suppression of last month's pro-democracy protests, earlier told reporters he had been confirmed as prime minister.

He said later that palace officials twice confirmed he would be the new prime minister, but that a third call from the palace said his nomination was off. Anand confirmed he was asked to serve about two hours before government-controlled television announced his appointment.

A government led by Somboon would almost certainly have sparked renewed protests, political instablity and a continuing decline in Thailand's once-booming economy.

Parliament Speaker Arthit Urairat told reporters Anand's short-term government was "meant to heal the country's present problems and especially its image in the international eye."

A brief statement to the king by Arthit said he presented Anand's name because of the public respect he earned as acting prime minister after last year's coup. Somboon had been the candidate of the pro-military governing coalition in Parliament.

Earlier Wednesday, Parliament overwhelmingly voted to amend the constitution to require that prime ministers be elected legislators and to reduce the powers of the military-appointed Senate. Anand did not run for a Parliament seat in March elections.