BANGKOK, Thailand -- A court dissolved Thailand's top three ruling parties for electoral fraud Tuesday and banned the prime minister from politics, bringing down a government that has faced months of strident protests seeking its ouster.

The Constitutional Court ruling set the stage for protesters to end their weeklong siege of the country's two main airports.

Cargo planes Tuesday resumed their services from Suvarnabhumi International Airport at 9:00 AM.

Government spokesman Nattawut Sai-kau said Prime Minister Somchai Wongsawat and his six-party ruling coalition would step down. "We will abide by the law," he told The Associated Press.

Somchai accepted the ruling with equanimity. "It is not a problem. I was not working for myself. Now I will be a full-time citizen," he told reporters in Chiang Mai.

Somchai's People's Power Party, the Machima Thipatai party and the Chart Thai party were found guilty of committing fraud in the December 2007 elections that brought the coalition to power with a thumping majority.

Court President Chat Chalavorn said the court was dissolving the parties "to set a political standard and an example."

"Dishonest political parties undermine Thailand's democratic system," he said in the court's ruling.

The ruling sends Somchai and 59 executives of the three parties into political exile, barring them from politics for five years. Of the 59 members, 24 are lawmakers who will also have to resign their parliament seats.

Deputy Prime Minister Chaowarat Chandeerakul will become the caretaker prime minister, said Suparak Nakboonnam, a government spokeswoman. She said parliament will have to pick a new prime minister within 30 days.