President Obama on Monday condemned the mass shooting at the Washington Navy Yard, calling it a "cowardly act" that "targeted our military and civilian personnel."

"We are confronting yet another mass shooting," said Obama in brief remarks at the White House before a scheduled speech on the fifth anniversary of the financial crisis.

He said that while military servicemembers regularly face danger abroad, “today they faced the unimaginable violence that they wouldn't have expected here at home.”

Obama said the victims at the naval base were “men and women going to work protecting all of us,” praising them as “patriots.”

Law enforcement officials said a lone gunman, identified as 34-year old Aaron Alexis, killed 12 people and wounded at least 10 others. Alexis was eventually shot and killed by police.

Obama signed an order for flags to be flown at half-staff through sunset on Friday to honor the victims.

The president also expressed thanks to law enforcement and first responders and to the doctors treating the injured at area hospitals.

In a statement, the White House said Obama “has been briefed throughout the day by Assistant to the President for Homeland Security and Counterterrorism Lisa Monaco and Deputy Chief of Staff Alyssa Mastromonaco about the ongoing situation and he continues to remain in contact with his team.”

Obama also contacted Secretary of the Navy Ray Mabus “to express his condolences to the families and colleagues of the victims.”

Reports said Alexis opened fire shortly after 8:30 a.m., Local and federal law enforcement officials sealed the Navy Yard compound and searched for the gunman throughout the morning.

Initial conflicting reports suggested multiple shooters and the Capitol Police for a brief time put the Senate office buildings on lockdown and flights into and out of Reagan National Airport were temporarily delayed.

The mass shooting is likely to renew debate on the nation’s gun laws, but the White House took a cautious approach on Monday.

White House press secretary Jay Carney declined to say if the incident would spark a new push by Obama for tougher gun control laws.

“It is far too early to say anything about who did this and the broader meaning of it,” Carney told reporters.

“What is true is that the president supports, as do an overwhelming majority of Americans, common sense measures to reduce gun violence,” he added.

After a gunman killed scores of children at Sandy Hook Elementary School in Connecticut last year, Obama launched a White House task force to address the nation’s epidemic of gun violence.

The president enacted a number of executive actions, but legislation has faltered in Congress. A measure to tighten background checks on firearm purchasers fell short in the Senate earlier this year.

Brian Hughes contributed.

This story was first published at 12:57 p.m. and has been updated.