Congressional lawmakers said they were shocked and saddened by the "cowardly" shooting rampage at the service's Washington D.C. headquarters Monday.
"There is nothing more cowardly than targeting innocents, and we have full faith in military and law enforcement officials to bring the perpetrators to justice," House Armed Services Committee Chairman Rep. Buck McKeon (R-Calif.) said in a statement.
“This is one more event to add to the litany of massacres that occur when a deranged person or grievance killer is able to obtain multiple weapons ... and kill many people in a short amount of time," Senate Intelligence Chairwoman Dianne Feinstein (D-Calif.) said in a separate statement.
Twenty children and six school staff members were shot by 20-year old Adam Lanza at the school in Newtown, Conn., before he turned the gun on himself.
On Monday, thirteen people were killed and several more wounded when a gunman opened fire at the Navy's headquarters in Washington.
Police identified the shooting suspect as Aaron Alexis, 34, of Ft. Worth, Texas. He was among the 13 killed, according to D.C. police.
"Today’s horrendous act [was] made all the more terrible because it happened in a place and to people who serve our nation and work to protect us," Sen. Jay Rockefeller (D-W.Va.) said in a statement.
Law enforcement are still looking for a second suspect Monday evening. At least one police officer was among the dozen wounded.
Alexis was identified as a former sailor who enlisted in the Navy in 2007 and served until 2011, according to biographical information released by the Navy. He reached the rank of petty officer 3rd class.
"Unfortunately, this is not the first time we've seen such a tragedy befall the patriotic personnel working at a U.S. military installation," McKeon said in the joint statement with panel ranking member Rep. Adam Smith (D-Wash.).
Former Army Maj. Nidal Hasan was sentenced to life in prison in August for killing 13 soldiers and wounding 32 in a mass shooting in 2009 at Ft. Hood, Texas.
Feinstein said both incidents show the need for gun control reform.
“Congress must stop shirking its responsibility and resume a thoughtful debate on gun violence in this country. We must do more to stop this endless loss of life," the California Democrat said.
Rockefeller (D-W.Va.), also a senior member of the Senate intelligence committee, echoed Feinstein's comments.
“We are becoming far too familiar with senseless, tragic violence ... and these repeated incidents demand our attention," he said.