Nine people were arrested during a protest at Union Square Wednesday, police and protest organizers said.

U.S. Capitol Police Lt. Kimberly Schneider said police charged eight protesters with illegal demonstration and another person with illegal demonstration and failure to obey a police officer.

The latter was a Washington Post photographer who stopped to photograph the protest, according to MaryAnne Golon, the Post’s director of photography.

Activists chained themselves to 50-foot tripods and hoisted themselves in the air to bring attention to the fight against AIDS, according to activist Lucile Scott, who attended the protest held at the Mall’s eastern end.

Scott said police arrived after six protesters had chained themselves to the tripods, which were erected to hang a banner supporting clean needles and a tax on billionaires to help fight HIV and AIDS.

Another two protesters were hoisted into the air with rock climbing harnesses, Scott said.

“Pretty quickly, the police came,” she said.