The protest against grand jury decisions not to indict white police officers for killing unarmed black men came to the steps of the U.S. Capitol Thursday.
More than 100 congressional staff members of all races, and several lawmakers, walked off their jobs and held their hands in the air in a gesture of surrender.
Senate chaplain Barry Black called the group a "voice for the voiceless."
This was the latest in a series of protests in cities across the U.S. against several highly publicized incidents in which unarmed black males died at the hands of white policemen.
Protesters have lain down in city streets and department stores and held so-called "die-ins."
A huge march on Washington organized by civil rights activist Al Sharpton is scheduled for Saturday.
Marchers frequently chant "I can't breathe" — the last words of crime suspect Eric Garner who died after white New York officer Daniel Pantaleo put him in a chokehold during an arrest. A grand jury declined to indict Pantaleo.
Another grand jury in Furguson, Missouri decided last month not to indict policeman Darren Wilson for the shooting death of unarmed black teen, Michael Brown during a street confrontation.
In Cleveland, Ohio, a police officer gunned down a 12-year-old black boy in a public park as the child waved what turned out to be a toy pistol.
A New York district attorney is considering charges against officer Peter Liang, who shot and killed a black man, Akai Gurley, in the stairwell of a Brooklyn apartment building. Police say Gurley was not a crime suspect and that the shooting was accidental.