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. At least 10 intersections were occupied by the protesters, who used buses to barricade major roads, spawning massive traffic jams. Police Gen. Vichai Sangparpai said there were up to 30,000 demonstrators. Ousted prime minister Thaksin Shinawatra, regarded by most of the protesters as their leader, called for a revolution and said he might return from overseas 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 phon message to followers who surrounded the prime's minister office. Political tensions have simmered since Thaksin was ousted by a military coup in 2006 for alleged corruption and abuse of power. He remains popular for his populist policies in the impoverished countryside, while his opponents – many in urban areas – took to the streets to help bring down two pro-Thaksin governments, seizing Bangkok's two airports in November for about a week. Army spokesman Col. Sansern Kaewkamnerd said soldiers and police were being moved to more than 50 key points in the city, including bus and railway stations. He said the military presence was not a sign of an imminent coup – a common feature of Thai political history. Abhisit's government suffered a major humiliation on Saturday when it failed to stop hundreds of demonstrators from storming the venue of a 16-nation Asian summit, forcing its cancellation and the evacuation of the leaders by helicopter. Abhisit vowed swift legal action against the protesters. A protest leader, Arisman Pongruengrong, was taken into custody Sunday and flown by helicopter to a military camp for questioning, said police spokesman Maj. Gen. Suport Pansua. There were signs Sunday that the government might again not be able to contain the protesters. Outside the Interior Ministry, a furious mob attacked Abhisit's car with poles, a ladder and even flower pots as it slowly made its escape. The prime minister's secretary and his driver were also attacked and badly injured. Police in riot gear nearby did nothing. “I believe that the people have seen what happened to me. They have seen that the protesters were trying to hurt me and smash the car,” Abhisit said in a television appearance. “The government can't do anything,” said Lada Yingmanee, a 37-year-old protester. “We will show them what tens of thousands of unarmed civilians can do. The people will finally rule our beloved Thailand.” Demonstrators from the United Front for Democracy Against Dictatorship say Abhisit's four-month-old government took power illegitimately and want new elections. They also accuse the country's elite – the military, judiciary and other unelected officials – of undermining democracy by interfering in politics. Abhisit was appointed by Parliament in December after a court removed the previous pro-Thaksin government for election fraud, sparking Thaksin supporters to take to the streets. Their numbers grew to 100,000 in Bangkok last week. The tensions have created a dangerous rift in Thai society, unleashing unprecedented passions among a large segment of the population. About 400 soldiers armed with rifles ringed Chitralada Palace, the Bangkok residence of King Bhumibol Adulyadej. But the monarch was believed to be at his seaside palace. “We told our people to be ready and be prepared,” said Jakrapop Penkair, a key protest leader. If the military uses force, “the people will be our weapon. We are not scared. Abhisit must be ousted immediately,” he said. Protests were also reported in areas of northern and northeastern Thailand, with one group threatening to blockade the main bridge linking Laos and Thailand across the Mekong River. “The situation has gotten completely out of hand. Violence and bloodshed is very much possible” if Abhisit does not resign or dissolve Parliament, said Charnvit Kasetsiri, a historian and former rector of Bangkok's Thammasat University. “If the government cannot control the situation, military intervention is not out of the question.”