The founder of the protest movement that shut down Bangkok's airports last year was shot and wounded in a possible assassination attempt Friday, just days after troops cracked down on rioting protesters from the rival, anti-government group.

The government quickly moved to tighten security around Prime Minister Abhisit Vejjajiva, who said a state of emergency that was imposed Sunday in Bangkok would remain in place. Vehicles carrying Abhisit were attacked twice by red-shirted protesters before and during this week's riots.

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Sondhi Limthongkul, a media tycoon and supporter of the current government, was in stable condition after surgery that removed "small pieces of bullet" from his skull, said Vajira Hospital director Chaiwan Charoenchoktawee. After the surgery, Sondhi was conscious and speaking and suffered no brain damage, he said.

Sondhi's People's Alliance for Democracy immediately said the attack was politically motivated, a claim that police said was under investigation.

The alliance — known as the "yellow shirts" — was behind protests last year to drive the allies of ousted Prime Minister Thaksin Shinawatra from power. His supporters come mainly from the middle class and educated elite of Thai society, and include royalists, academics and retired military.

Those demonstrations, which paralyzed the government for months and occupied the capital's airports for a week, only ended after court rulings removed two Thaksin-allied governments, paving the way for Abhisit's rise in December.

But the rulings set of protests by the yellow shirts' rivals — the red shirts who are staunch supporters of Thaksin and argue Abhisit had no popular mandate to rule. Their demonstrations came to a height in Bangkok earlier this week but were called off Tuesday after facing a major military crackdown.

The red shirts, who come largely from rural areas, have expressed anger that several of their leaders were arrested over the past week, while Sondhi and his allies were never prosecuted over last year's airport seizures, which stranded some 300,000 travelers.

Abhisit said Friday that the Cabinet had decided not to revoke the emergency decree that was imposed Sunday to control rioting in the capital.

"We are concerned by the shooting obviously. We've got to restore order," Abhisit said, indicating the government was worried the attack could lead to another flare-up of violence. "We do not want this to be used to create a wider conflict."

Government spokesman Panitan Wattanayagorn told reporters that security around Abhisit would be increased and "we may not be able to disclose his plans and schedule as usual."

Sondhi, who owns the pro-government TV channel ASTV, was being driven to work before dawn Friday when at least two men in a pickup truck ambushed his car and opened fire with M-16 and AK-47 rifles, first aiming to shoot out the tires and then spraying the vehicle with bullets, said Bangkok police spokesman Suporn Pansua.

"Considering the nature of the attack and the weapons used, we believe it was carried out by people with expertise," Suporn said, adding that 84 bullet shells were found on the road. "We believe the attack was meant to take lives."

The car's windshield was riddled with bullets and windows on one side were shattered. The driver of the car was seriously wounded and an aide traveling in the car also was wounded, Suporn said.

A spokesman for Sondhi's alliance, Panthep Poapongpan, said it was "quite clear" that the attack was politically motivated but stopped short of saying who he believed was behind it. Sondhi regularly travels with bodyguards.

None of the leaders of the red-shirt movement could be immediately contacted. Aside from three in police custody, others were on the run and had their phones switched off.

Police said an investigation was under way to determine the motive and that they were looking into Sondhi's political and business enemies who could be linked to the attack.