Iraq War veteran Scott Olsen, 24, lays on the ground bleeding from a head wound after being struck by a by a projectile during an Occupy Wall Street protest in Oakland, Calif., Oct. 25, 2011. (Jay Finneburgh/AP Photo)

With tensions mounting daily, the name Scott Olsen has become a national rallying cry for the Occupy Wall Street movement.

Olsen, a 24-year-old Iraq veteran, is in serious condition after suffering a fractured skull during clashes with police in Oakland.

He joined the protests after work Tuesday night and suffered his head wound when police fired tear gas into the crowd during the crackdown. People who came to his aid were then scattered by a gas canister tossed by police.

In an effort to show solidarity with Olsen and their counterparts in Oakland, protesters in New York City marched to City Hall on Wednesday night. The demonstration led to a tense confrontation with police and 10 arrests.

Today, the police union said officers had showed restraint but the union would sue any protester who injured an officer.

So are the confrontations entering a dangerous new stage?

Many city officials are under pressure from constituents tired of unsightly tent cities, dead grass and dangerous conditions. The cost to already struggling municipalities, which must protect and clean up after the protesters, is soaring.

“We know for a fact we’ve crossed the $300,000 threshold in terms of money spent so far for this operation,” said Atlanta Mayor Kasim Reed.

In San Francisco, the bill is more than $100,000.

“It’s just something that has to happen, it’s a worldwide movement,” said protester Dustin Sneed, who has been at the San Francisco protest since the beginning.

Across the country, the figures are growing. In New York City, overtime costs are $3.4 million. In Minneapolis, the sheriff’s department reports spending $200,000. And in Boston, the tally is $2 million and counting.