This is a developing story ... 

At least four people were shot Thursday morning in a Washington, D.C., neighborhood within walking distance of the White House, with one person reportedly dead.

The shooting occurred at about 8 a.m. at the Vida Gym in the city's upscale Logan Circle neighborhood, about a mile from the White House. Police described the location as an "active" scene, with the shooter barricaded and reportedly exchanging gunfire with police. 

The city's Metropolitan Police Department issues a shelter-in-place warning to residents on their cellular devices.

The fatality is being reported by local TV station FOX 5. 

The incident has resulted in a massive law enforcement response, with the National Guard and numerous federal agencies at the scene. Helicopters are above the crime scene, and police snipers are on roofs. 

Authorities have asked people to avoid the area near the 1500 block of 15th Street, crossing P Street, which has been cordoned off. The area includes St. Luke’s Episcopal Church, a Whole Foods supermarket and residences.