The incident occurred near Dupont Circle, where hundreds were gathered for the Capital Pride Parade. No shots were fired but several people were injured while running away from they feared were gunshots, tweeted Kevin Donahue, D.C. Deputy Mayor for Public Safety and Justice.
The Washington Post reported a law enforcement source said a fight broke out in the circle and a gun was possibly brandished. Police found a gun inside a backpack, but no description of the weapon was given. Authorities told WRC-TV that one person was being questioned.
One witness told the Post that "everyone started running behind us, running and screaming." One city official told the paper that five people suffered injuries consistent with fleeing from a scene.
Medical personnel treated some of those injured. The parade ended early after the incident.
The Associated Press contributed to this report.