Thousands of protesters marched across Pakistan on Thursday, torching pictures of President Asif Ali Zardari as a nervous government put paramilitaries on alert and detained 30 lawmakers. Lawyers and political activists took to the streets after the main opposition leader, former premier Nawaz Sharif, called for action when the Supreme Court barred him from running for election and holding public office. Security forces sealed off the Punjab provincial assembly but thousands of people stormed the barricades for a sit-in outside the governor's residence in Lahore, punching their fists in the air before dispersing, witnesses said. A crowd of up to 5,000 protesters torched two large hoardings showing Punjab Governor Salman Taseer and beat pictures of Zardari with sticks and shoes before setting them ablaze. Hundreds more rallied elsewhere in Lahore. Many shops across the country closed and the government, alarmed about the angry public reaction to the court ruling, deployed riot police.