Security officers once again patrol the Suvarnabhumi Airport, in Bangkok, Thailand, Tuesday. Anti-government protesters who shut down the airport for nearly a week agreed to clear out within 24 hours after Prime Minister Somchai Wongsawat said he would comply with a court decision and step down. (Ed Wray/Associated Press)

Demonstrators occupying Bangkok's two main airports have announced they will end their siege within 24 hours as a Thai court dissolved the three largest parties in the ruling coalition.

People's Alliance for Democracy leader Sondhi Limthongkul said Tuesday that thousands of anti-government protesters who have been camped at Suvarnabhumi international airport and the domestic Don Muang airport will leave by Wednesday morning.

Airport officials said cargo flights have already resumed and passenger flights would resume on Friday.

More than 300,000 passengers from around the world have been stranded since demonstrators took over the two airports last Tuesday. About 2,000 Canadians were affected by the protests.

The announcement that the siege would end came hours after Thailand's Constitutional Court found Prime Minister Somchai Wongsawat's People's Power Party, the Machima Thipatai party and the Chart Thai party guilty of having committed electoral fraud in late 2007. Somchai and other party executive members were found guilty and banned from politics for five years.

However, rank-and-file members of the three parties can join other factions and try to cobble together a new coalition and choose a new prime minister. Somchai is expected to remain caretaker prime minister until then.

Constitutional Court President Chat Chalavorn said the "court has decided to dissolve the party to set a political standard and an example."

"Dishonest political parties undermine Thailand's democratic system," he said.

Demonstrators who blocked access to the airports believe the country's government is controlled by ousted former prime minister Thaksin Shinawatra. They were calling for the resignation of Somchai. He is the brother-in-law of Thaksin, who fled the country two years ago to escape corruption charges.

With files from the Associated Press