|Rival protest groups have each been aggressively campaigning for a prime minister of their choice [Reuters]
A Thai court has ordered more than a dozen key leaders of a protest group to pay up millions of dollars for occupying Bangkok's airport in 2008.
The civil court on Friday said the group "illegally interfered" in the operation of Bangkok's two main airports during the protest, which left more than 300,000 travellers stranded and caused major damage to Thailand's economy.
The People's Alliance for Democracy (PAD), better known as the Yellow Shirts, had sought to force out the then prime minister, Somchai Wongsawat, the brother-in-law and political ally of the country's ousted former prime minister Thaksin Shinawatra.
"The defendants incited protesters, through their speeches, to occupy the airports," the verdict said.
Among the defendants was Chamlong Srimuang, the controversial former Bangkok governor.
The protest leaders were ordered to pay $17.2m, plus interest, to Airports of Thailand PCL, the semi-state-owned airport operator.
The court rejected suggestions that the yellow shirt demonstration could have constitutional protection, saying that the rally was not peaceful and some protesters were armed.
The protest leaders also face criminal charges, but have yet to go on trial.
The Southeast Asian country has seen aggressive protests by both yellow-shirted and rival red-shirted movements since a 2006 bloodless military coup ousted Thaksin from office.
The agency closed the two airports for security reasons, disrupting travel for thousands of passengers, and demonstrators defied an injunction calling for them to leave.
Panthep Wongpuapan, a spokesman for PAD, said the group will appeal the ruling.
"We did nothing wrong," he told The Associated Press.
"We have clear evidence, which is a clip of the AOT [airport operator] governor saying that he was the one who ordered the closure of the airports. We just got onto their premises."
Earlier in 2008, yellow-shirted protesters occupied the prime minister's office for three months.
Peaceful PAD protests set the stage for the 2006 coup, which the military justified by accusing Thaksin of corruption and disrespect to the monarchy.
When Thaksin's political allies returned to power in a December 2007 election, the so-called yellow shirts initiated more aggressive protests to try to force them out, using confrontational tactics that were later adopted by the rival red shirts who support Thaksin.
Thai court rulings forced two pro-Thaksin prime ministers out of office in 2008, and parliamentary maneuvering installed the rival Democrat Party in power.
Thaksin's allies say the courts and the Democrats are pillars of the establishment, which felt its power threatened by Thaksin's huge popularity with Thailand's poor and working classes.