Police beat and arrested youths, rioters smashed windows and fires were lit in the streets of Barcelona on Wednesday as a student demonstration against economic cuts boiled over. Hooded rioters hurled paving slabs through the glass door of a bank and police charged other protestors, beating them with batons, handcuffing some and hauling them off, an AFP photographer saw. Thousands of students were marching in various Spanish cities in anger over crisis spending cuts that are hitting schools and universities and at recent police violence against protesters in Valencia. Demonstrators swamped the streets in the eastern city of Valencia, the region worst hit by the education funding crisis, and in Madrid hundreds marched to the Puerta del Sol square in a rally that passed peacefully. But in Barcelona clashes broke out, blamed by police on a small group. One hooded rioter faced off with a bank employee who warded him off with a pole, while elsewhere bins stood in flames among ranks of riot trucks and officers with shields and helmets, AFP photographs from the scene showed. "A small group started throwing heavy objects at the officers and the front of the stock exchange building" in the city centre, a police spokesman who asked not to be named told AFP by telephone. "The crowd was dispersed and arrests were made," he added, without saying how many. "Most of the demonstration carried on and a small group behaved violently." An AFP reporter at the Mobile World Congress, a mobile telecom industry gathering taking place in the northeastern Spanish city, said police put up barriers to protect the venue from the disturbances. Protestors marched through the streets in various towns after some camped the night in universities in a movement dubbed Primaveraestudiantil ("Student Spring") and Tomalafacultad ("Seize the faculty") on Twitter. The national students' union said marches were called in about 40 cities and towns across the country to protest the austerity measures they say are disrupting classes and cutting teaching jobs. "We did not create this crisis but we are paying for it in every sense," said the union's leader Tohil Delgado ahead of Wednesday's marches, saying classes and thousands of teaching jobs have been cut. "They are making cuts in public education, they are giving us no option to work, and on top of this, when we protest democratically, they beat us with complete impunity." He estimated turnout at the Valencia demonstration alone was in the tens of thousands. In Madrid students whistled and chanted slogans such as "Fewer cuts, more education!" They rallied noisily outside the national education ministry and stopped on their march to whistle angrily outside offices of Santander, a major bank. They were the latest in a string of demonstrations in various sectors in anger at cuts and reforms that the conservative government says will strengthen the economy and eventually curb unemployment, which is near 23 percent. "All the cutbacks and the labour reforms make it hard for youths to enter the labour market," Diego Parejo, 21, a third-year politics student, at the Madrid demonstration, told AFP. "When I finish university, I see a very dark future."