BANGKOK - Tens of thousands of protesters converged on Bangkok's main shopping area on Saturday and threatened to stay until Thailand's premier calls elections, forcing big retailers to close and paralyzing traffic. The red-shirted protesters swarmed an intersection whose upmarket stores make it a symbol of wealth in the Thai capital, accusing Prime Minister Abhisit Vejjajiva's government of neglecting the poor on the 21st day of their mass street rally. Central World, the second-largest shopping complex in Southeast Asia, and other big shopping malls shut their doors in response to the protests and threats by the "red shirts" to stay in the area popular with tourists and studded with hotels. "We cannot let Mr. Abhisit rule the country any longer," Jatuporn Prompan, a "red shirt" leader, said from the roof a truck. "It is time for the under-privileged to liberate themselves from oppression made by the elite-backed government." While the rally was mostly peaceful, tensions flared when protesters smashed the windshield of a Porsche sports car that had driven onto a sidewalk and hit a demonstrator. Police rescued the 18-year-old driver, the son of a prominent businessman. Thousands also rallied outside state-controlled broadcasters Radio Thailand and Channel 11, accusing them of bias. Backed by Thailand's powerful military and royalist establishment, Abhisit has said a peaceful poll now would be difficult given the tensions and has offered to dissolve parliament in December, a year early.