The shooting occurred late Sunday night in "the area of 14th and U Street, NW", a popular area filled with stores, restaurants and bars, Xinhua news agency quoted the Metropolitan Police Department as saying.
Metropolitan Police Chief Robert Contee told reporters that a 15-year-old was killed while three adults -- two civilians and one police officer -- were wounded but are expected to survive.
D.C. Police Union tweeted that the officer who was shot "has been transported to the hospital and is in stable condition".
A free music festival marking Juneteenth was being held in that area when the shooting broke out and caused panic among the crowd.
Contee said the event was held without permission.
The incident came a day after shots were fired inside a large shopping mall in Virginia, near Washington, D.C.
No one appeared to have been shot but three people were taken to the hospital for injuries suffered while they were fleeing from inside, according to police.
More than 20,000 people have died due to gun violence across the US so far this year, according to the latest data from Gun Violence Archive.
Metropolitan Police Chief Robert Contee told reporters that a 15-year-old was killed while three adults -- two civilians and one police officer -- were wounded but are expected to survive.
D.C. Police Union tweeted that the officer who was shot "has been transported to the hospital and is in stable condition".
A free music festival marking Juneteenth was being held in that area when the shooting broke out and caused panic among the crowd.
Contee said the event was held without permission.
The incident came a day after shots were fired inside a large shopping mall in Virginia, near Washington, D.C.
No one appeared to have been shot but three people were taken to the hospital for injuries suffered while they were fleeing from inside, according to police.
More than 20,000 people have died due to gun violence across the US so far this year, according to the latest data from Gun Violence Archive.