A man has been arrested for allegedly assaulting a paramedic and breaking his leg at the Occupy Wall Street site overnight.

Police say paramedics were called to Zuccotti Park for a man who was acting irrationally.

When they arrived, the man in question appeared to be in emotional distress and police decided he needed to be taken to the hospital. But authorities say protesters formed a human chain to block the police as the man refused to go.

"We were denied access to the patient, and people were actually blocking us from transporting," said FDNY Commissioner Salvatore Cassano.

One of the EMTs was pushed into a ladder, fracturing his leg.

The man is being charged with assault.

Before the incident Wednesday, Mayor Bloomberg defended the protesters as law-abiding folks who keep to themselves and don't cause trouble.

"I will say, in all fairness to the people down there, we watch very carefully, they generally do not break the law," Bloomberg said on MSNBC's "Morning Joe" program Wednesday.

"When they protest, they march in a line, they stay on the sidewalks, they follow the direction of the police, they exercise their First Amendment rights... And we haven't seen the kinds of things you see in other cities where people are running through the streets destroying commerce and reputation," he said.

"If you go one block away from this park, you would never know it exists," he went on. "It's just literally -- in any direction, one block away -- there's just nothing."

Last week, Bloomberg griped that Lower Manhattan was suffering under the movement that began Sept 17.

"This isn't an occupation of Wall Street," he said at the time, "it's the occupation of a growing, vibrant, residential neighborhood in Lower Manhattan and it's really hurting small businesses and families."