Police cited a man for violating park rules Thursday night at Thomas Square park, where Occupy Honolulu has an encampment.

Officers stopped by the park about 10:05 p.m., explained the park rules, and verbally warning the protesters to leave the park when it is closed, police said. Thomas Square is closed from 10 p.m. to 5 a.m., according to the city’s website.

Officers made a routine check of the area about 11:40 p.m. and found a cardboard structure on the grass in the park. Police said a man sleeping within the structure had been present at the initial warning, and he was issued citations for violating park rules and closing hours.