BANGKOK – The founder of Thailand's "yellow shirt" protest movement that shut down Bangkok airports last year was shot and wounded in an assassination attempt Friday, just days after troops cracked down on rioting protesters from the rival, anti-government "red shirt" 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 in the run-up to this week's riots.