Several people were shot and killed in the headquarters of the Naval Sea Systems Command in the Navy Yard this morning. The shooter is dead, according to the Metropolitan Police Department. One MPD officer and two other victims were taken to Washington Hospital Center for treatment. About 3,000 people work in the headquarters. See below for updates.

Update, 4:36 p.m. The FBI has revealed the identity of the shooter who was killed earlier today. He was 34-year-old Aaron Alexis of Fort Worth, Texas, and the FBI has posted information about him here. At a press conference, Valerie Parlave, the FBI assistant director in charge of the Washington field office, said anyone with information about Alexis should contact the bureau. “We are looking to learn everything we can about his recent movements, his contacts, and his associates,” she said.

Mayor Vince Gray said that the number of fatalities is now 13, following the death of one victim in a hospital. He reiterated that officials do not know the shooter’s motive.

MPD Chief Cathy Lanier said after the first shots were reported this morning, MPD officers were on the scene within two to three minutes, at which point security within Navy Yard had already engaged the shooter. Within seven minutes, Lanier says, an “active shooter team” was in the building and had “multiple engagements” with the shooter, the last of which resulted in his death.

Update, 3:16 p.m. An MPD spokesman says the white man in the tan outfit is neither a suspect nor a person of interest. However, MPD is still searching for a person described as a black man with graying sideburns in an olive uniform.

Also, tonight’s Washington Nationals game at Nationals Park, just a few blocks from the shooting, has been postponed until tomorrow at 1 p.m.

Update, 2:20 p.m. At a press conference, Mayor Vince Gray and Police Chief Cathy Lanier said there are at least 12 fatalities. “We have no known motive,” said Gray, adding that they have “no reason” to think this morning’s shootings were acts of terrorism.

Lanier said MPD is searching for two potential suspects in addition to a shooter who was killed. She described one as a white male in a beret-style hat between 40 and 50 years of age, who was wearing a tan military-style uniform consistent with U.S. Navy garb; and a black male of medium complexion with gray sideburns, who was wearing an olive uniform, has gray sideburns, and who is about 5 foot 10 inches and 180 pounds. She said investigators do not know if the suspects are members of  the Armed Forces.

Asked why the men are suspects, Lanier said, “Right now we have multiple pieces of information that would suggestion we have at least two other individuals with firearms,” adding, “We have reason to believe that these people may be involved, and we need to talk to them.”

Lanier said the FBI has taken the lead on the investigation, and that anyone with information should call 1-800-CALL-FBI.

Another press conference is scheduled for 4 p.m., and officials have asked residents to stay clear of the Navy Yard area. “We are still doing an extensive search,” Lanier said. “The remainder of the search could take a couple of hours.”

Update, 12:20 p.m. MPD Chief Cathy Lanier says one shooter is dead, and Mayor Vince Gray says “as far as we know, this is an isolated incident.” Multiple victims are also dead, Lanier says. Police are still looking for what could be two more shooters, one a black man wearing an olive-drab military-style uniform, the other a white man wearing a short-sleeve khaki Navy-style uniform. “The big concern for us right now is that we potentially have two other shooters that we have not located at this point,” Lanier told a press conference near the Navy Yard. “This is not confirmed… We have no information to believe either of those folks are military personnel, but we do have information that both of them are wearing military uniforms.” If you see them, call police.

Update, 12:01 p.m. The Navy says family members of people who work in the building can call for information:

Update, 11:50 a.m. MPD spokeswoman Gwendolyn Crump says reports that there was also a shooting at Joint Base Anacostia-Bolling are false: “There was no shooting at Bolling.”

Update, 11:38 a.m. Three victims are at Washington Hospital Center, one an MPD officer and two civilians, Chief Medical Officer Janis Orlowski told a press conference there. All three are alert, but “they do have severe injuries.” The MPD officer, a man, has gunshot wounds to his legs. One of the civilians, a woman, has a gunshot wound in her shoulder; the other has gunshot wounds in her head and hands. “Their chances of survival are very good,” Orlowski says.

Update, 10:51 a.m. A Metro spokeswoman says MPD requested at least four Metro buses to transport witnesses, which the transit agency has provided.

Update, 10:37 a.m. A spokeswoman for Navy Public Affairs confirms there have been multiple fatalities. The Washington Post is reporting that four are dead.

Update, 9:58 a.m. A spokeswoman for MPD says 10 people have been shot. MPD describes the shooter, who is “still active,” as a black male around six feet tall and 170 pounds wearing a black shirt and hat.

Update, 9:35 a.m. According to the Washington Post, an MPD officer was shot near a room where the shooter has barricaded himself. Police confirmed “multiple injuries” to City Desk, and said that the incident is still “active.” Several news outlets are reporting that MPD says at least four people have been shot.

Original post: At least least one person was shot this morning at the headquarters of Naval Sea Systems Command in Navy Yard, according to the U.S. Navy. The Metropolitan Police Department and the Fire and Emergency Shooter Department are currently on the scene in on M Street SE responding to the “active shooting,” according to D.C. officials.

The police department confirmed at least one victim, though the D.C. Fire Fighters Association tweeted at around 8:40 a.m. that there were multiple victims. According to the U.S. Navy’s Twitter feed, the shooter is “still active” as of 8:51 a.m.

A U.S. Navy press release says a “shelter in place” order has been issued for Navy Yard personnel. About 3,000 people work in the Naval Sea Systems Command’s headquarters.

Due to an editing error, the post originally reported at least three people were shot, when, at the time, just one injury had been confirmed.

Photo by Darrow Montgomery