At least 12 activists were arrested after refusing to leave Baltimore's City Hall early Thursday as they protested a move to make the city's interim police commissioner permanent.

At least 25 police officers converged outside the building hours before dawn as activists were still inside. Several of the demonstrators could be seen by an Associated Press reporter as they were led off in plastic handcuffs and loaded into transport vehicles.

"It is our duty to fight for our freedom! We have nothing to lose but our chains!" others watching the police operation shouted at the officers.

Police said in a statement posted on their social media site that a small number of protesters had decided to leave after hours of warnings to the demonstrators.

"The remaining protesters refused to leave the building. As a direct result of their failure to comply, the remaining protesters have been arrested and charged with trespassing. There are no reported injuries at this time to any protesters or officers," the police statement added.

Police did not elaborate on the number of people arrested or their identities. A message left for Baltimore Police Department spokesman T.J. Smith wasn't immediately returned.

Following the police operation, police were seen leaving and the complex was largely quiet by 5 a.m.

The drama began late Wednesday as several members of the Baltimore Uprising coalition shouted from the balcony overlooking the meeting room as the city council subcommittee prepared to vote for Kevin Davis as permanent commissioner. The group refused to leave until Davis and Mayor Stephanie Rawlings-Blake met their list of demands, including changes to police tactics and significant investment in education and social services.

Some of those who had left before the arrests said they were mostly student activists. They said they opposed city deliberations to make permanent the interim appointment of Police Commissioner Kevin Davis, adding they had been given no chance for input and had several other demands.

"All we are doing is peacefully demonstrating. We were disrespected by Kevin Davis. He didn't take us seriously," said Kevin Wellons, a 19-year-old man who left the sit-in around 3:30 a.m. with several others after protesters received a police warning.

Kwame Rose, an organizer for the protesters who were occupying the building, told The Associated Press he and others left after police had warned they shouldn’t be in the building after hours. Rose said he was upset Davis hadn’t met with the activists to listen to their demands.

Baltimore police told the Baltimore Sun that after “hours of communication and warnings, a small number of protesters inside of City Hall decided to leave the building.” Police said the remaining protesters were arrested and charged with trespassing.

The subcommittee meeting to discuss Davis’ appointment drew a large crowd with some supporting the decision to name Davis as full-time police commissioner and others blasting the decision.

"All night, all day, we will fight for Freddie Gray!" the activists chanted amid calls to postpone the vote. "No justice, no peace!"

Three of the subcommittee's five members voted in favor of Davis. Councilman Nick Mosby, who is married to State's Attorney Marilyn Mosby, voted against the confirmation, while Carl Stokes, who is running for mayor, abstained. The council’s appointment committee approved the appointment, which will now go to the city council on Monday.

It was Marilyn Mosby who decided to prosecute six officers in connection with Gray's death. All of the officers are currently awaiting trial. In the aftermath of Mosby's decision and the widespread unrest, homicides began to rise and residents in crime-addled neighborhoods accused police officers of abandoning their posts.

Following the subcommittee's vote, Davis called Wednesday night's protest an "act of civil disobedience" that "is just part of this moment."

"It's all part of the healing process," he said. "The fact that this occurred isn't upsetting. It's just part of where the city is right now. I understand where they are. I understand their frustration. ... I promised the citizens of Baltimore and the protesters that I'll be the type of police commissioner that they deserve. This is just part of where the city is right now, and if we're going to get to the other side of this, we have to go through these moments."

Addressing the council subcommittee earlier, Davis said that he remains committed to training officers to actively engage and interact with community members. Davis also emphasized his commitment to "respect and fight for the right for Americans to assemble and peacefully protest."

"2015 is the year that things change," Davis said, referring to the task of repairing the tense relationship between the police and the public in Baltimore.

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The Associated Press contributed to this report.