U.S. Park Police arrested dozens of Occupy D.C. protesters who refused to dismantle an unfinished wooden structure they built in a park overnight.

On Sunday morning, police told them they'd need a permit and gave them an hour to disassemble it.

When the protesters failed to comply, officers arrested several protesters. After an hours-long standoff, an inspector posted a notice on the structure and later more protesters inside it were arrested.

Police say 31 people have been arrested and that they have dismantled the structure. By late Sunday, six protesters who had been on the roof came down aboard a cherry picker.

No protesters remained in the building and police remain at the encampment.

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   Courtesy Associated Press