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A gunman who terrorized the Navy Sea Systems Command headquarters building in Washington, D.C., was shot and killed after carrying out a shooting spree that left four others dead and at least ten injured, according to officials.

The shooter is described as a former Navy official in his fifties whose work status was recently changed, reports ABC News. His name has not been released.

SWAT officers swarmed the building amid reports of another gunman who might be at large.

“We may have two additional shooters out there,” D.C. Police Chief Cathy Lanier said during a noon press conference.

The two at large suspects were dressed in military garb but are not believed to be U.S. service personnel, Lanier said.

One was a young white man in a khaki-like uniform and the other was a black man in olive-colored garb, she said.

There is “no hard evidence” of a second gunman, according to NBC News.

WATCH: Live coverage of shooting rampage at D.C. Navy base

The Pentagon Force Protection Agency has “increased its security posture, not out of a specific threat, but as a proactive, precautionary measure related to the ongoing incident at the Navy Yard.”

This means more officers at Pentagon entrances armed with automatic weapons, according to Lt. Col. Tom Crosson, a Pentagon spokesman.

The U.S. Capitol Police are also conducting “enhanced security operations” on the U.S. Capitol grounds, though there is no known threat to the complex at this point.

Eyewitnesses described the gunman as a black male dressed in all black, carrying an “assault rifle” and a double-barreled shotgun.

Terrie Durham, who works at the Naval Sea Systems Command building, said the gunman appeared to be wearing dark fatigues. “He was tall. He appeared to be dark-skinned,” she told WJLA-TV.

“He was a tall black guy,” said her co-worker, Todd Brundidge, who is black. “He didn’t say a word. He aimed the gun and fired our way, I couldn’t believe it.”

People frantically tried to run out of the building, Brundidge said.

“Everyone was going down the stairs. They were pushing. They were shoving. People were falling down,” he told the TV station. “As we came outside, people were climbing the wall trying to get over the wall to get out of the spaces. It was just crazy.”

Rick Mason, a program management analyst who is a civilian with the U.S. Navy, told the Associated Press that a gunman was shooting from a fourth floor overlook in the hallway outside his office. He said the gunman was aiming at people in the building’s first floor cafeteria.

Shooting victim treated at scene

Police spokesman Chris Kelly described the suspect as an adult male, about 6 feet tall with a bald head and medium complexion, dressed in a black top and black jeans.

A naval security guard was among those shot and was hit in both legs, U.S. military officials said. Washington city police told WRC, the NBC affiliate in Washington, that one of their officers was also among those shot. It was not clear how many of the others shot were civilian and how many were military.

The Navy said on its Twitter feed that shots were fired at 8:20 a.m. ET at the headquarters of the Naval Sea Systems Command, part of the Washington Navy Yard.

The Washington Navy Yard says on its website that it’s the Navy’s oldest shore establishment and the largest of the Navy’s five system commands. It’s home to the chief of Naval Operations and is also headquarters for the Naval Historical Center and numerous naval commands. It builds, buys and maintains the Navy’s ships and submarines and their combat systems.

WNEW: Photos from scene of Navy Yard shooting

The Navy Yard is on lockdown and a “shelter in place” order has been issued, the Navy says. Approximately 3,000 people work at the facility.

Tim Hogan, a spokesman for Rep. Steven Horsford of Nevada, posted photos to his Twitter account of people tending to at least one person down on a street corner.

President Barack Obama lamented that the U.S. is “confronting another mass shooting” and called for a seamless investigation involving federal agencies and the military.

“I’ve been briefed by my team on the situation. We still don’t know all the facts, but we do know that several people have been shot and some killed. So we are confronting yet another mass shooting, and today it happened on a military installation in our nation’s capital. It targeted our military and civilian personnel, men and women who were going to work, doing their job protecting all of us. They are patriots. And they know the dangers of serving abroad, but today they faced the unimaginable violence that they won’t have expected here at home.”

This is a breaking news story. More to come …

Read more at http://www.wnd.com/2013/09/active-shooter-on-grounds-of-washington-navy-yard/...