Multiple people were killed and several more wounded when at least one gunman opened fire Monday at the Naval Sea Systems Command headquarters, authorities said.

The Navy said "several" people were killed at the Navy Yard. Local media said at least three were dead and several more people were wounded.

Washington's Metropolitan Police Department reported that a suspect was on the loose in the building. The shooter was described as a black male with a dark complexion, approximately 5'10" to 6 feet tall, 170 pound with a black shirt and black hat. He is believed to be barricaded somewhere and have multiple guns.

The Navy day began with the Navy reporting on its Twitter feed that there was an "active shooter" at Building 197 at the Navy Yard, and that three shots had been fired at 8:20 a.m. ET. The Navy later reported deaths and injuries, but details remained fluid.

Flights at nearby Washington Reagan National Airport were being disrupted, with all departures halted at the airport as of 10 a.m. ET.

The White House released a statement: "The president has been briefed several times about the unfolding situation at the Washington Navy Yard by Assistant to the President for Homeland Security and Counterterrorism Lisa Monaco and Deputy Chief of Staff Alyssa Mastromanaco. The President directed his team to stay in touch with our federal partners, including the Navy and FBI, as well as the local officials. We urge citizens to listen to the authorities and follow directions from the first responders on site."

They announced this on their Twitter feed??

The first thing they thought when this happened was "Oh, I'd better update the status on Twitter". Ridiculous. No wonder the world laughs at Yanks.

nothing like waking up in the morning and learning there's a shooter on the loose half a mile from where you live.

A story posted on the Web site of the Fort Worth Star-Telegram Monday said that Alexis was arrested in 2010 for illegally discharging a firearm. The paper cited a Fort Worth police report that said police had been dispatched to Alexis’ apartment complex about 6:40 p.m. Sept. 4, 2010, on a report that someone had fired a shot through the floor and into the ceiling of a woman’s apartment.

Police found that Alexis had fired a shot through the ceiling of his apartment, missing his upstairs neighbor by a few feet. Alexis later said his gun had gone off while he was cleaning it, the paper said.

Police found that Alexis had fired a shot through the ceiling of his apartment, missing his upstairs neighbor by a few feet. Alexis later said his gun had gone off while he was cleaning it

"In the weeks before the attack on the Navy Yard, Alexis reported hearing voices and said that three people were sending vibrations through the ceiling to keep him from sleeping, police said Tuesday.

"Police in Newport, R.I., said that Alexis called them to a Marriott hotel there on the morning of Aug.

"7 and reported that he was being followed and was worried that the people were going to hurt him.
Alexis told police that the three talked to him through the walls, floor or ceiling at three hotels — two commercial hotels in Rhode Island and one on a naval base there. He told them that they used a microwave machine to send vibrations and keep him awake."