Nearly 700 people were arrested overnight in rowdy demonstrations in Montreal and Quebec over a planned hike in student tuition fees with rocks being hurled at police, a spokesman said Thursday. Police in Montreal had said the unsanctioned protest would be tolerated if there was no trouble but after some unruly behavior around midnight they moved in and arrested 518 demonstrators. Another 170 people were detained in Quebec. All were issued with a more-than $600 fine and released on Thursday morning, the police spokesman said. Several thousand demonstrators had poured into Montreal\'s central square late Wednesday for the rally, defying a law passed last week requiring organizers to notify authorities eight hours ahead of public demonstrations. Of those arrested in Montreal, 506 were held for unlawful assembly but among the other 12 detentions one person was held for \"armed aggression,\" two others for assaulting police, and one more was detained for wearing a mask. Protesters said they were handcuffed and their arms held behind their back, local media reported. Demonstrations have raged in Montreal since mid-February over a plan by provincial Premier Jean Charest and his Liberal Party to raise tuition fees at Quebec universities by 82 percent, or $1,700, over five years in order to rein in a budget deficit. Some of the demonstrations have turned violent, with store fronts smashed. The conflict escalated on Sunday with more than 300 overnight arrests after the passing of the controversial new law governing demonstrations. Bill 78 prohibits freedom of assembly anywhere in the francophone province without prior police approval and requires protesters to give the authorities eight hours\' notice before an event and follow a planned route. Rather than quelling the unrest, it appears to have made things worse for the embattled premier. The crisis has already felled one cabinet member, education minister Line Beauchamp, who said she was quitting politics altogether because she had \"lost confidence in the goodwill of student leaders.\" Tens of thousands of demonstrators ignored their official itinerary on Tuesday as they took to the streets of Montreal to mark the 100th day of the movement. \"People are backing the students because Charest went too far,\" said Jacques Hamel, a sociology professor at the University of Montreal. \"It\'s a threat to fundamental rights, freedom of expression, freedom of association.\" After nine years in power, Charest hoped an initially popular hike in fees might boost his dismal poll numbers, but months of building protests coupled with disapproval for the new law appear to have had the opposite effect. A poll released on Tuesday by the Journal de Montreal found an 18 percent shift in favor of the students, compared to a poll taken 10 days previously. The QMI/Leger Marketing survey still showed the students trailing the government by eight points on the central question of who respondents supported, but the momentum has clearly turned. Some 53 percent of respondents agreed that Bill 78 went \"too far,\" while 32 percent judged it to be fair and eight percent believed it didn\'t go far enough.