SAN FRANCISCO — Lawyers from the Federal Public Defender’s office filed a startling motion Tuesday claiming that their counterparts at the U.S. Attorney’s Office for the Northern District of California have taken part in a racially biased drug enforcement effort.

In court papers filed Tuesday, Federal Public Defender Steven Kalar and a group of his assistants claim that raids conducted in 2013 and 2014 as part of the Operation Safe Schools initiative resulted in the arrests of 37 people in San Francisco’s Tenderloin neighborhood, and all of them are black.