Some "Occupy Chicago" protesters joined up with anti-war protesters on Thursday outside President Barack Obama's 2012 campaign headquarters at Chicago's Prudential Plaza.

“Occupy Chicago” began on September 23, when around 20 people gathered at Willis Tower, formerly known as the Sears Tower, and then marched to the Federal Reserve Bank to show their solidarity with the “Occupy Wall Street” protesters in lower Manhattan.

Since the beginning of the protest, dozens to hundreds of protesters have demonstrated at a busy corner outside the Federal Reserve Bank of Chicago. Their Twitter page now boasts over 8,000 followers.

“We went from having just a handful of people at the beginning,” one of the protesters, Mark Banks, told Chicagoist. “Now everyday there’s dozens and dozens of people during the daytime and as the evening goes on, as people get out of school and out of work. Yesterday we had over 100 people at our last general assembly meeting, so the numbers are just going through the roof.”

The "Occupy Chicago" protesters apologized on Thursday for a person who joined up with the group, but later committed vandalism.

"Occupy Chicago gratefully welcomes anyone who wishes to participate in this movement," they said. "Unfortunately, this has led to individuals who attempt to use Occupy Chicago to promote their own agendas and act without the groups best interest in mind."

The protesters later said they suspected that "inciters" might be trying to create tension between the Chicago police and the demonstration.

The Chicago Police previously told the Associated Press that the demonstration had been “very peaceful” and that the police department had maintained open lines of communication with the group.

The protesters had been camped outside the Federal Reserve Bank of Chicago, but were forced to move their encampment Wednesday when police informed them they risked fines or arrest if they didn't move their supplies. A Chicago ordinance prohibits storing personal property in a public way.

In response, the protesters moved their belongings to a nearby church and vowed to continue the occupation.