President Barack Obama
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Officials confirm that 10 people have been shot and Obama says "some have been killed."

Charlene Cooper
Sep, 16, 2013

President Barack Obama addressed the country Monday following a mass shooting at the Washington Navy Yard in Washington, D.C.

The president's message was geared toward comforting the families of the victims as he vowed to bring the perpetrators to justice.

"We will do everything in our power to make sure whoever carried out this cowardly act is held responsible," he said.

Details on the shooting are still developing, but officials have confirmed that one gunman is dead and two others may still be on the loose. The fatal shooting has left at least 10 people shot and several killed.

Obama, who's been briefed all morning by his security team, is being kept abreast on the shooting by counterterrorism adviser Lisa Monaco and Deputy Chief of Staff Alyssa Mastromanaco.

Watch President Obama's address below.