After being on lockdown for hours, the U.S. Navy confirmed that no shooting took place Thursday morning at the Washington Navy Yard, after reports of an incident there.
In a press conference late Thursday morning, Washington Mayor Muriel Bowser said that a Navy Yard employee reported at approximately 7:29 a.m. that "she may have heard gunshots in the facility."
After an hours-long police and federal law enforcement sweep, "there's no evidence of gunshots, there's no evidence of a shooter and there's no evidence of any victims today," Bowser said.
The D.C. Police Chief Kathy Lanier will host a meeting to examine law enforcement response.
Navy Admiral Dixon Smith said at the press conference that the Yard remains in lockdown as police finish up a final sweep of building 197; it's been locked down since just before 8 a.m. He expects to open up the Yard after the walk-through is completed at approximately 11:30 a.m.
In September 2013, a gunman killed 12 and injured three others at the Navy Yard before being shot and killed by Washington Metropolitan police. The shooting occurred in building 197.
Thursday morning's incident comes almost a week after the FBI, the Department of Homeland Security and the National Counterterrorism Center warned of potential terrorist threats around the Fourth of July weekend. Police in several cities responded to the notice by boosting security measures.
But despite those warnings, Lanier said the police response was no different Thursday from what was done two years ago during the last Navy Yard shooting.
"I think it has nothing to do with the increased threat level," she said. "That's what we do every day here."
Lanier said there's no evidence that the reports were a "malicious hoax," and that the employee who called in the initial reports was following standard procedure.
The Navy Yard has been on lockdown since just before 8 a.m. as police continue their investigation.
The U.S. Navy confirmed on Twitter at 7:59 a.m. that the building complex in southeast Washington had been placed on lockdown, but not the exact nature of the incident.
NBC News and the Associated Press said early on that shots were reported at the Yard. Shortly after 10 a.m., the AP reported that no shots were fired at the military base, citing a law enforcement official. WUSA reported that D.C. fire officials say no injuries have been reported.
Navy spokesman Chris Johnson could not initially confirm to National Journal that no shooter was spotted, only that an active investigation is in place. He said that employees inside building 197, where the incident was reported, have been evacuated. According to the Navy’s latest tweet, a Naval Criminal Investigative Service investigation is still ongoing.
Police have blocked streets in the base's vicinity as officers, emergency medical crews, and the FBI have descended on the area. M Street has been closed between South Capitol Street and 11th Street Southeast. Helicopters circled the scene Thursday morning, and police have swept and cleared the nearby Navy Yard Metro station.
For those who remember the Navy Yard shooting two years ago, the false alarm still stirred up the trauma that hit the same building in 2013.
"My heart dropped. I almost came to tears," says Brent Whelan, who worked in building 197 in 2013.
Two years ago, he had nearly entered the building when he saw colleagues rushing out. "Something happening today, it really hits close to home," Whelan said.
"The response brings it all back," says Liliana Houndershell, who also worked in 197, but had taken her first personal day in 11 years on the morning of the shooting.
Whelan and Houndershell sat on a median on M Street just outside of Navy Yard, hoping for the best, but with the memory of the last tragedy still fresh. While both said they underwent mandatory trauma counseling and participated in group therapy sessions with co-workers, the emotion was still rushing back.
"You think you are past it and you're not," Houndershell said. "I thought I was good."
Capitol Police said Thursday it has boosted security on the Capitol grounds in response to the reported incident at the Navy Yard. "We have additional units in the field deployed strategically around the Capitol complex, as the situation dictates, while remaining available to continue to provide mutual support at the Navy Yard," Capitol Police spokeswoman Lt. Kimberly Schneider said.
This is a breaking story and will be updated with more information.
Lauren Fox, Rachel Roubein and Dustin Volz contributed to this article.