MONTREAL - Four people were injured during student protests as Quebec's battle over university tuition-fee hikes took a nasty turn Wednesday.

Clouds of tear gas wafted over downtown Montreal as riot police used billy clubs to slam their way through protesters who were blocking a public building. Some responded by tossing snowballs at officers.

Though the injuries were all minor, two people -- one policeman and one protester -- had to be whisked away by ambulance to have their wounds treated in hospital.

The scene in Montreal's streets illustrated the increasingly bitter battle over fees, pitting the Charest government against those who deem the province's rock-bottom tuition rates an inviolable right.

It also served to highlight the student pushback that in the past has dissuaded Quebec governments from increasing rates, which have remained frozen in the province for 33 of the last 43 years while authorities either avoided or abandoned plans for hikes.

Students converged Wednesday on several provincial buildings, including the liquor commission and the education minister's office, and they momentarily attempted to occupy the Loto-Quebec headquarters which is home to the organization representing university rectors.

Helmeted and shielded police charged a line of students near the Loto-Quebec headquarters after they pushed down a row of metal barriers. They also came in swinging on the front steps of the building, knocking away students who were blocking the entrance.

One student said police overreacted, claiming he was "brutalized" for a simple act of civil disobience. Frank Levesque-Nicole was hit by a baton in the base of his skull and was blinded with blasts of pepper spray by the group of officers who surrounded him.

"I was only standing there blocking the door, but obviously the cops didn't see it that way," Levesque-Nicole said. "They ... hit us very hard.

"I saw people with nosebleeds, which basically was uncalled for. The biggest weapon people had were snowballs -- what kind of a threat is a snowball to someone in full body armour?"

Five students were arrested, some tackled by police who fixed plastic ties around their wrists before hauling them away.

The boom of volleys of tear gas echoed through the street as riot-squad officers laid down a curtain of gas among the protesters, sending many stumbling away coughing and rubbing at their eyes. Some protesters apparently gained a brief entry at Loto-Quebec headquarters but were moved out. Others jostled a row of police bicycles, while some tossed objects at officers.

The melee was eventually brought under control with lines of police facing mobs of protesters across Sherbrooke Street, one of Montreal's main east-west arteries. Barriers and debris littered the street and a Quebec provincial police helicopter soared above the scene tracking the mob's movements.

Students are protesting increases in tuition fees that the government plans to implement during the next five years.

Quebec's tuition rates for in-province students are the lowest in Canada, although students coming from other provinces are made to pay higher rates.

The provincial government says its planned increases -- at an extra $325 for each of the next five years -- will still leave Quebec with some of the lowest tuition rates in the country at $3,793 per year. It says the new rates will help ensure the quality and sustainability of Quebec's universities.

However, students protesting the hikes call it a question of values.

They say higher fees would discourage some people from going to university, and also believe money to pay for better schools is available from other sources in Quebec.

Tens of thousands of students have declared a strike and walked out of their classes in recent weeks. However, others have voted against taking such action or even voiced support for the hikes.

Premier Jean Charest was digging in his heels Wednesday. He described his government's plan as a reasonable and equitable way to keep universities competitive.

"The real question is the quality of post-secondary education in Quebec. That's the issue," Charest told a news conference.

"It's through taxpayers here ... that we're going to do the lion's share of fianncing of our universities and colleges. Then we're asking students to assume their fair share."

Charest added that bursaries will increase at the same rate as tuition, to help poorer students: "So it's a fair solution," he said.