SANTIAGO, Chile -- Dozens of students and other protesters interrupted a Senate committee meeting Thursday to demand a popular referendum on how to resolve Chile's social problems, especially education. Some protesters climbed atop the committee room's table and unfurled a sign reading "Plebiscite now" as Education Minister Felipe Bulnes and others participating in the hearing by the Senate's education budget subcommittee hurriedly left. Activists shouted and threw coins at Bulnes, who stumbled during scuffling on the way out, while a young man broke a window. The protesters then occupied the Senate headquarters in Santiago and transmitted the situation live over the Internet by webcam. They urged other students to converge on the building, which housed Chile's congress before the 1973-90 military dictatorship, and then march to the presidential palace Thursday night. Police blocked more people from entering the building and confronted a crowd outside, where protesters held signs demanding "Free Education" and "Referendum Now." The occupation of the Senate headquarters came just hours after riot police violently evicted protesters from galleries at the current Congress building in Chile's port city of Valparaiso. Senate President Guido Girardi, a member of the opposition, promised that the protesters at the Senate building would not be dislodged by force. His promise drew criticism from pro-government legislators, including Sen. Alberto Espina, who criticized Girardi for "a serious dereliction of duty" in failing to ensure the security of the committee hearing. University and secondary school students have been boycotting classes and mounting demonstrations for nearly six months, pushing their demand that the government make extensive changes in Chile's education system. The protests have been largely peaceful, but small groups of activists have frequently fought with police after the marches end. The protesters are demanding that the government provide free public education for all students, not just the poorest, and to improve the quality of schooling. They also want state subsidies for private colleges reduced. President Sebastian Pinera's government has said it cannot afford to make education free for all Chileans, and student leaders have broken off negotiations with the center-right administration. Pinera has sent his own proposals for education changes to Congress, and appointed a commission of experts to provide him with further ideas in January. Political leaders on both the right and left have said the issue will have to be resolved in Congress, but student leaders say they want a national referendum because they don't trust legislators. The protests have won widespread sympathy for the students, while Pinera's support has dropped to between 20 percent and 30 percent in opinion polls. But Chile's constitution allows referendums in only very limited circumstances, such as when Congress and the president cannot resolve their differences.