By Amie Parnes - 09/16/13 04:55 PM EDT
President Obama on Monday said the nation was "confronting yet another mass shooting," calling the victims of the Washington Navy Yard tragedy "patriots" who faced the "unimaginable violence they wouldn't have expected at home."
"They know the dangers of serving abroad, but today, they faced the unimaginable violence they wouldn't have expected at home," Obama said.
At least four people were killed and eight others were wounded in a shooting early Monday at the Naval Sea Systems Command Headquarters at the Navy Yard in Washington.
The president said he was closely monitoring the unfolding situation but added, "we still don't know all the facts."
"We do know that several people have been shot and some have been killed," he said.
He vowed to "do everything in our power" to make sure that whoever committed the "cowardly act" would be brought to justice.
"Obviously we're going to be investigating thoroughly," Obama said.
White House press secretary Jay Carney said later that the president expected "seamless cooperation" between federal, military and law enforcement agencies as they responded to the crisis.
The press secretary said that the Navy Yard shooting remained an "active investigation and an active situation," adding that because "we don't have all the facts" it was "hard to comment on this situation."
"The president supports, as do a majority of Americans, commonsense measures to combat gun violence," Carney said.
Justin Sink contributed to this report.
This report was updated at 1:46 p.m.