Former Reservist Identified as Navy Yard Gunman

Twelve people are now dead after a Monday morning shooting at the Washington Navy Yard. Law enforcement officers shot dead one suspect and searched the grounds for two possible accomplices as the number of fatalities climbed to 11.

At a Monday afternoon briefing, Washington Police Chief Cathy Lanier said "at least 12 are confirmed dead at this point" and several others were wounded. She did not give the conditions of the wounded but said the wounded included one police officer who was shot in the leg.

Officials have identified the gunman as Aaron Alexis, 34, o f Ft. Worth, Texas, according to multiple media reports. Alexis was a Navy employee whose work status had been changed earlier this year, a federal government official told the Associated Press. He was also a former Navy reservist.

Lanier also said "we have no indication of any motive at this time." She stressed repeatedly that the hunt was underway for two other possible suspects who were seen carrying weapons at the scene, and she urged neighborhood residents to remain in their homes.

"We have reason to believe these people may be involved and we want to talk with them," Lanier said.

One potential suspect was a white male about 40-45 years old carrying a handgun and wearing tan, military-style clothes and a beret, Lanier said.

The other possible suspect was described as a black male about 50 years old who was wearing olive-drab clothes and may have been carrying a rifle, Lanier said.

The shootings began at about 8:20 a.m. inside Building 197, headquarters of the Naval Sea Systems Command.

Witnesses described a gunman opening fire from the fourth floor, aiming down on people in the first-floor cafeteria. Others said a gunman fired at them in a third-floor hallway.

Todd Brundidge, an executive assistant with Navy Sea Systems Command, said he and other co-workers encountered a gunman in a long hallway of their building on the third floor. The gunman was wearing all blue, he said.

"He just turned and started firing," Brundidge said.

Terrie Durham, an executive assistant with the same agency, said she also saw the gunman firing toward her and Brundridge.

"He aimed high and missed," she said. "He said nothing. As soon as I realized he was shooting, we just said, `Get out of the building.'"

Patricia Ward, a logistics management specialist, said she was in the cafeteria and heard shots. They sounded like "pop, pop, pop," she said. After a few seconds, there were more shots.

"Everybody just panicked at first," she said. "It was just people running, running, running."

Ward said security officers started directing people out of the building with guns drawn.

The shooting was initially believed to have been carried out by a single gunman carrying a long gun, possibly an AR15 military-style rifle.

Most of the victims were shot inside Building 197, headquarters of the Naval Sea Systems Command, but Navy Cmdr. Tim Jurus later told reporters that a male individual he did not know was shot while standing next to him outside the building.

Jurus, who works at Building 197, said he left the building after hearing gunfire and a fire alarm go off. Jurus also said that he had later seen the dead gunman, who had been shot in the head.

Last week, a day after the 12th anniversary of the 9/11 attacks, Al Qaeda leader called for random attacks on the U.S. to bleed the nation economy. In an audio speech released online, al Zawahiri said "We should bleed America economically by provoking it to continue in its massive expenditure on its security."

Washington, D.C. , Mayor Vincent Gray, who was also at the afternoon briefing with Lanier, isn't so sure.

"As far as we know this is an isolated incident, we don't know of any other installations involved," he said.

There had been reports of shots being fired at Bolling Air Force Base in southeast Washington, but Air Force and law enforcement spokesmen said the reports were unfounded.

"We're really not prepared to answer questions at this time" on whether the shootings were terror related or may been been a workplace incident, Gray said.

Capitol Police secured the Capitol grounds, the Federal Aviation Administration grounded planes at Reagan National Airport and federal buildings throughout the Washington Metro area went on alert as the first reports of the shootings went out.

District of Columbia schools officials said six schools and one administrative building in the vicinity of the Navy Yard were placed on lockdown. The action was taken out an abundance of caution, schools spokeswoman Melissa Salmanowitz said.

More than 3,000 military and civilian personnel work at Building 197 and they were either being evacuated or told to "shelter in place," said Navy Lt. Cmdr. Sarah Flaherty, a Navy spokeswoman.

Naval Sea Systems Command is the largest of the Navy's five system commands and accounts for a quarter of the Navy's entire budget. It builds, buys and maintains the Navy's ships and submarines and their combat systems.

Defense Secretary Chuck Hagel relased a statement on the shooting: "I have been receiving regular updates on the shooting at the Washington Navy Yard, and continue to monitor the situation closely. This is a tragic day for the Department of Defense, the national capital area, and the nation.  My thoughts and prayers are with the victims of this outrageous act of violence, their families, and all those affected by today's events.  I am grateful for the swift response of federal and local law enforcement, and for the professionalism of DoD personnel at the Navy Yard complex. The Department of Defense will continue to offer its full assistance in the investigation of this terrible and senseless violence."

--The Associated Press contributed to this report.