Eighteen protesters connected to the nationwide Occupy movement were arrested Saturday outside the presidential campaign headquarters of Republicans Michele Bachmann, Newt Gingrich and Rick Santorum.

Local police in suburban Des Moines, Iowa, say the 16 adults and two juveniles were arrested for trespass, a simple misdemeanor. Most were released later Saturday.

Dozens of demonstrators massed outside the office where Bachmann had come to rally staff and make calls to potential caucusgoers. Campaign security told the protesters not to approach the office.

Urbandale police Lt. Kent Knopf said the 10 Occupy demonstrators were arrested, handcuffed and taken away in squad cars from Bachmann’s office after they ignored security, who called police.