WASHINGTON, April 22 — Two adults were critically wounded and a child suffered a minor injury in a shooting today near a college preparatory school in Washington, D.C., and police swarmed the area searching for suspects, authorities said.

Details of the shooting were sketchy. No motive was known for the shooting, which erupted in late afternoon in an upscale neighbourhood of Northwest Washington along Connecticut Avenue, a major thoroughfare through the city.

Two of the victims, a man and a woman found wounded near the Edmund Burke School, a private preparatory academy, were hospitalized in critical but stable condition, and a juvenile victim suffered a minor gunshot wound, according to Assistant Police Chief Stuart Emerman.

He said police fanned out across the neighbourhood looking for possible perpetrators, but had no immediate description of any suspect. Emerman said several individuals seen fleeing the scene were briefly detained for questioning but none were believed to have been involved.

"At this time, I do not believe that we have any suspects at this time detained,” Emerman said.

"We’re looking for any suspect or suspects. We do not have a motive at this time,” Emerman told reporters. "We do not know the full details of what took place. But we continue to ask the public to just steer clear of the area as we continue to investigate.”

One eyewitness told local television station WUSA-TV he heard a burst of rapid gunfire lasting about a minute, and saw a woman running out of a building who appeared to have been grazed by a gunshot, followed by other individuals who were apparently wounded.

The eyewitness said he saw other people on the street taking cover behind parked cars and pointing up to a balcony where they presumably believed the gunshots originated.

A WUSA reporter posted a short video on Twitter of another witness identified as Austin Bittle who said he was in a nearby coffee shop when he heard more than 20 gunshots ring out in quick succession before seeing police officers racing toward the scene.

According to the District of Columbia’s Metropolitan Police Department, the shooting unfolded in the 4100 block of Connecticut Avenue in the city’s northwest quadrant near the Burke School.

"I was in the building and I was getting ready for track practice, but then I heard loud noises and glass was shattering behind me. A bunch of us just got out of the building and ran,” one unidentified student told local ABC affiliate WJLA-TV in an interview from a liquor store, where the youth had taken cover.

News footage on local television showed Connecticut Avenue blockaded by emergency vehicles. Dozens of police vehicles, with flashing lights, were parked outside the school building, as police in full tactical gear and some in camouflage assembled nearby.

"It was madness. I mean, it’s just unbelievable,” Jade Moore, an Edmund Burke parent, told WJLA of the incident, which she said left her daughter huddled inside a classroom until police escorted her and other students to a safer part of the campus. "You know, you think they’re safe, but you’re not safe anywhere.”

The upscale neighborhood also is home to several foreign embassies, Howard University School of Law, and the Van Ness campus of the University of the District of Columbia, which said on Twitter that it had been placed on a security lockdown.

A second well-known prep school, the Sidwell Friends School, also was reported by local media to be on lockdown. — Reuters