Occupy Oakland wasn't deterred when the city tried to evict them from their camp at Frank Ogawa Plaza, nor was it deterred when a police officer threw a flash bang explosive into a group of people, nor when an Iraq War veteran named Scott Olsen was hit by a tear gas canister and lay bleeding from the head on the pavement.

It seems the clash that happened between police and the anti-Wall Street greed protestors only invigorated their cause.

Late Wednesday night to early Thursday morning, the Occupy Oakland protestors marched past the city hall plaza where they've been living for 15 days. Olsen, who suffered a fractured skull and brain swelling, was certainly on their minds.

The irony is not lost on anyone here that this is someone who survived two tours in Iraq and is now seriously injured by the Oakland police force, Olsen's friend, Adele Carpenter, told Reuters.

I'm going to stay here tonight, Oakland resident Jhalid Shakur told MSNBC. I don't have a tent, but I'll sleep on a bench if there's space.

We're about to build our city back, he said.

Oakland city officials reneged on their evacuation notice, allowing the 1,000 or so protestors back into their tented camp. Occupy Wall Street has pledged to send $20,000 and 100 tents to Oakland.

Acting Oakland Police Chief Howard Jordan said his department was opening an investigation into the incident, but wouldn't comment on how or why Olsen was struck.

It's unfortunate it happened. I wish that it didn't happen. Our goal, obviously, isn't to cause injury to anyone, the chief said at a press conference.

Oakland Mayor Jean Quan said the city welcomes and supports the protests, but alleged that a small number of the demonstrators on Tuesday night threw rocks at police officers who tried to block their path.

We had, on one hand, demonstrators who tried to rush banks, other demonstrators saying don't do that, and we had police officers, for the most part, 99 percent, who took a lot of abuse, said the mayor. So yesterday was a sad day for us.

The Occupy Oakland protests are part of the Occupy Wall Street movement against corporate greed that began in New York over a month ago. The movement has spread to a number of cities across the country, including Atlanta, where police evicted dozens of people from a park and arrested more than 50 who refused to vacate.

At Occupy Orlando, demonstrators who were told to leave a park overnight had their belongings confiscated by the police, according to Reuters. In Baltimore, police have told protestors that only one tent could stay overnight on Wednesday, instead of 200.