President Obama vowed Monday to hold responsible those who carried out the "cowardly" mass shooting at the Washington Navy Yard, while calling the victims "patriots" who served their nation.
Details are still emerging about the shooting. Officials say one gunman is dead, but one other may still be at large. Police say 13 people, including the shooter, have been killed.
"We are confronting yet another mass shooting, and today it happened on a military installation in the nation's capital," Obama said.
The president had planned to speak Monday morning to address the five-year anniversary of the financial crisis. He went on to discuss his economic agenda, saying it's been his "No. 1 priority," but addressed the shooting at the top and spent the morning being briefed by his security team.
A White House official said counterterrorism adviser Lisa Monaco and Deputy Chief of Staff Alyssa Mastromanaco are keeping the president updated on the shooting.
Obama lamented that those caught in the crossfire on Monday knew of the dangers abroad, but "today they faced the unimaginable violence that they wouldn't have expected here at home."
He said he's ordered a "seamless" investigation. "We will do everything in our power to make sure whoever carried out this cowardly act is held responsible," he said.
Obama has directed his team to stay in touch with federal and local officials. The Defense Department and Washington's Metropolitan Police Department are taking the lead on the response. The Department of Homeland Security, along with the National Counterterrorism Center, are monitoring the situation.
"We urge citizens to listen to the authorities and follow directions from the first responders on site," a White House official said.
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.
Pentagon spokesman George Little said Monday that the department's "thoughts and prayers" are with the victims.
"This is a fluid situation," he said. "Navy officials are working closely with law enforcement and emergency management representatives from the FBI and the District of Columbia to secure the scene and begin the investigation."