President Barack Obama and first lady Michelle Obama attend a memorial service for the victims of the Washington Navy Yard shooting at Marine Barracks Washington Sunday, Sept. 22, 2013. A gunman killed 12 people in the Navy Yard on Monday, Sept. 16, 2013, before being fatally shot in a gun battle with law enforcement. The president and first lady Michelle Obama also visited with the victims' families. (AP Photo/Charles Dharapak)
President Barack Obama hugs a family member at a memorial service for the victims of the Washington Navy Yard shooting at Marine Barracks Washington Sunday, Sept. 22, 2013. A gunman killed 12 people in the Navy Yard on Monday, Sept. 16, 2013, before being fatally shot in a gun battle with law enforcement. The president and first lady Michelle Obama also visited with the victims' families. (AP Photo/Charles Dharapak)
President Barack Obama memorialized the victims of the Washington Navy Yard shooting as patriots but also individuals — one with a talent for fixing cars, another who coached softball and yet another who loved hockey and her cats.
It's not enough to cry over their deaths, Obama said.
"If we really want to honor these 12 men and women, if we really want to be a country where we can go to work and go to school and walk our streets free from senseless violence without so many lives being stolen by a bullet from a gun, then we're going to have to change," the president said.
Speaking Sunday at the city's Marine Barracks, just blocks away from where the shootings happened a week ago Monday, Obama called on Americans not to give up on trying to change gun laws that he argued are to blame for an epidemic of violence.
Gun control measures Obama had backed failed to pass Congress earlier this year and showed no new momentum in the days following the rampage at the Navy Yard, a military installation just blocks from the Capitol.
Obama said that when such tragedies strike, "it ought to be a shock to all of us, it ought to obsess us. It ought to lead to some sort of transformation."
But, he said, "nothing happens." Obama said he sometimes fears "there is a creeping resignation that these tragedies are just somehow the way it is, that this is somehow the new normal. We cannot accept this."
He acknowledged "the politics are difficult," a lesson he learned after failing to get expanded background checks for gun buyers through the Democratic-controlled Senate this spring, a measure he proposed after the shooting at Connecticut's Sandy Hook Elementary School killed 20 first-graders and six staff.
He said that by now "it should be clear that the change we need will not come from Washington, even when tragedy strikes Washington."
"Change will come the only way it ever has come, and that's from the American people," he said.
The invitation-only crowd Obama spoke to at the Marine Barracks parade ground included more than 4,000 mourners, with the victims' family members directly in front of the speakers' stage. The president and first lady Michelle Obama met privately with the families before the service, White House officials said, and both hugged family members as they left.
Authorities say their loved ones' lives were taken Monday September 16 by shotgun-wielding former Navy reservist, Aaron Alexis, a 34-year-old information technology contractor who struggled with mental illness. Police killed Alexis in a gun battle.
Obama said it's clear from the Navy Yard shooting that the country needs to do a better job to secure its military facilities and improve mental health services, but also address gun laws.
"I do not accept that we cannot find a common-sense way to preserve our traditions, including our basic Second Amendment freedoms and the rights of law-abiding gun owners while at the same time reducing the gun violence that unleashes so much mayhem on a regular basis," Obama said, adding the change may not happen soon but it will happen "because it is the change that we need."
National Rifle Association Executive Vice President Wayne LaPierre rejected any call for gun control. "The problem is there weren't enough good guys with guns," LaPierre said on NBC's "Meet the Press."
The military leaders who spoke before Obama at the memorial service included Defense Secretary Chuck Hagel, Navy Secretary Ray Mabus and Adm. Jonathan Greenert, chief of naval operations.
Washington Mayor Vincent Gray also called for action, saying "our country is drowning in a sea of guns."
The service ended with a bugler playing taps and a reading of the names of the fallen. They ranged in age from 46 to 73 and included civilian employees and contractors. A bell sounded as each name was read.
Peggy McFarland, 56, attended the ceremony and said she agreed with the president's words. McFarland, who works in building 197 where the shooting took place and said she always greeted the security guard Richard Ridgell who was killed, said she too is frustrated by gun violence.
"I think that we shouldn't accept this as the norm," she said, echoing the president, and adding, "It can't be like this."
Associated Press writers Nedra Pickler, Philip Elliott and Stacy A. Anderson contributed to this report.