Hundreds of protesters stormed the grounds of Thailand's parliament Wednesday, forcing government ministers to flee by helicopter and raising pressure in a four-week street rally seeking snap elections. The incident prompted the Thai authorities to declare a state of emergency in the capital. The red-shirted supporters of ousted premier Thaksin Shinawatra retreated from the parliament but tens of thousands remain in Bangkok's main shopping district, refusing orders to leave until Prime Minister Abhisit Vejjajiva dissolves parliament. The scene outside parliament was among the most chaotic and confrontational since the sporadic protests began on March 12. Protesters massing outside gates of the sprawling complex pressed up against a line of police in full riot gear. When some “red shirts” forced open the iron gate, police melted away and hundreds swarmed on to the grounds, including dozens packed on a truck that drove into the main entrance. They pressed up against security forces outside the lobby doors but left after about 20 minutes only to regroup outside the gates, brandishing guns and tear-gas canisters they said were seized in scuffles with military police. Deputy Prime Minister Suthep Thaugsuban and several other ministers scaled a wall in the compound and escaped by military helicopter. Some had left before the break-in, including Abhisit. Despite the tension, Thai stocks and the baht currency rose on confidence the government, with support from the military and the royalist establishment, will survive the increasingly bold showdown with the mostly rural and working class protesters. Finance Minister Korn Chatikavanij, however, said prolonged protests could inflict damage on the economy, Southeast Asia's second biggest, by causing output this year to be “significantly worse” than a government projection of 4.5 percent growth, and possibly delay an expected interest rate rise. Threats to arrest the protesters have not been carried out, emboldening a movement that has tapped an under-current of frustration over a level of income disparity that ranks among Asia's widest according to World Bank statistics. An Internal Security Act that allows troops to impose order was also extended on Wednesday for two more weeks. But there was no sign of an imminent crackdown as “red shirts” parade through the city on motorbikes, cars and pick-up trucks, waving red flags. Army chief Anupong Paojinda, who is central in Thailand's balance of power, said there was no justification to use force to disperse the crowds, an unidentified source told the Bangkok Post newspaper. “We can't since it will cause losses,” he quoted Anupong as telling Abhisit. “They all are Thais.”