Pro-Michael Brown demonstrators interrupted the St. Louis Symphony's concert on Saturday night.
Following an intermission, the symphony was about to perform Johannes Brahms' "Requiem" when audience members stood up one-by-one in the Powell Symphony Hall and sang Florence Reece's 1931 song "Which Side Are You On?"
Three banners were lowered from the balcony in support of Brown who was shot and killed by Ferguson, Mo., Police Officer Darren Wilson on Aug. 9, notes the St. Louis Post-Dispatch (video below).
While some audience members were shocked, there was applause from others in the crowd and members of the orchestra.
After the song ended, the protesters left the hall chanting, “Black lives matter” and dropping red paper hearts that read, “Requiem for Mike Brown.”
"It was certainly unexpected. I think it took everyone in the hall by surprise," Erika Ebsworth-Goold, publicist for the St. Louis Symphony, told Fox 2 News.
"There were a number of patrons inside the hall who were apparently very moved by what these people had to say," added Ebsworth-Goold.
"These were people who had paid money to come see the concert. They were patrons of ours, and we`ll discuss it certainly, but I can`t see any major security protocol changes at this point."