Thailand's ousted prime minister called for a revolution Sunday after rioting erupted in the capital, with protesters commandeering public buses and swarming triumphantly over military vehicles in unchecked defiance after the government declared a state of emergency. Bands of red-shirted anti-government protesters roamed areas of Bangkok, with some furiously smashing cars carrying Prime Minister Abhisit Vejjajiva and his aides and others beating up motorists who hurled insults at them. Ousted Prime Minister Thaksin Shinawatra, regarded by most of the protesters as their leader, called for a revolution and said he might return from exile to lead it. "Now that they have tanks on the streets, it is time for the people to come out in revolution. And when it is necessary, I will come back to the country," he said in a telephoned message to followers who surrounded the prime's minister office.