Police say that as he was led away by officers, Singh threatened to return and shoot the other man.
The seven people taken to hospital had non-life-threatening injuries which were received during the panic, police said.
"About a of the contributors within the crowd mentioned there turned into once a person with a gun and that someone had fired a shot", mentioned Commander Guillermo Rivera of the Metropolitan Police Department.
A reporter for CNN affiliate WJLA that he heard three or four very loud pops he thought were gunshots. Police said several people were injured as the result of the panic reaction by them.
The incident occurred near Dupont Circle, where hundreds were gathered for the Capital Pride Parade. "In the partially open bag, Maio reported he saw what appeared to be a silver handgun", the news report said.
Messi unseats Mayweather as highest-paid athlete
Manchester United's Paul Pogba is the highest earning Premier League player in 44th place with $49.8 million. Athletes had to earn a minimum of $25m (£19.6m) to make this year's list.
Trump renews Mexico tariff threat amid row over migration deal
Trump left a conflicted impression of who is driving the secret agreement and when the public might see it. The president said that it's his "option" as to whether the undisclosed agreement will go into effect.
Ashleigh Barty Creates History At French Open 2019
Barty was the beneficiary of the next twist, winning the next five straight games. " Oh, it's incredible ", she said. Konta was winless at the French Open until this year, having gone out in the first round four consecutive years.
Inside a small park in Dupont Circle, Singh pulled the BB gun on another person who was "hitting on his significant other", according to a police report.
Mayor Muriel Bowser, in a statement posted on Twitter, confirmed that no shots were fired and said fire department personnel were "on the scene to treat minor injuries / due to reports of a shooting".
"We can not allow this incident, until we know all the facts of it... to ruin the pride celebration going on this weekend", said Ashley Smith, president of Capital Pride Alliance, which organizes the annual event. He said the group spends extensive time planning security procedures.
Rivera said police felt they had an "adequate amount of resources on the ground, which is why we were able to respond so quickly". The alert police immediately arrested him and his BB gun was captured from his brown bag.
Jordan said Singh and Duffy were expected to appear in court on Monday for an arraignment.