President Obama played the dual roles of consoler-in-chief and gun-control advocate Sunday, as he paid tribute to the 12 lives violently ended in the Washington Navy Yard mass shooting and urged the nation to take action against gun violence.

“Once more our hearts are broken. Once more we ask why. Once more we seek strength and wisdom through God's grace,” Obama said at a memorial service at the parade grounds of the Marine Barracks.

He lamented the latest mass shooting, saying the American public must demand tougher gun-control measures to prevent killings.

“Sometimes I fear there is a creeping resignation --- that this is somehow the new normal,” he said. “We can't accept this… we are going to have to change.”

"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 added.

Some 4,000 people attended the private memorial. Defense Secretary Chuck Hagel, Navy Secretary Ray Mabus and Mayor Vincent Gray also spoke, each honoring the unique lives of the victims, who ranged from 46 to 73, and were murdered just blocks from the Capitol.

Aaron Alexis, a Navy contractor, on Monday afternoon opened fire in Building 197 on the Navy Yard, killing 12 and wounding eight others before he was killed by police.

At the close of the ceremony, the president went into the crowd and hugged each victim’s family members.

The role of consoler-in-chief is a familiar one for the president. He attended an interfaith vigil following the mass shooting at Sandy Hook Elementary School in Newtown, Conn.; a memorial service after the Tucson, Ariz. shooting; a memorial service for the 12 people killed in a movie theater shooting Aurora, Colo.; and another for those killed at Fort Hood, Texas.

At each service, Obama tried to strike the right balance between acknowledging the lives and service of those who died and expressing his anger over the nation’s mass shootings.

One of the victims, 51-year-old Arthur Daniels, lost his 14-year-old son to gun violence in 2009, and for his surviving family “old wounds have been ripped open again,” Obama said.

After 20 children were gunned down at Sandy Hook last year, Obama pushed tougher background checks and bans on military-style assault weapons and high-capacity clips, but those measures failed to gain traction in Congress.

Obama shared details about the personal lives of the Navy Yard victims in his address, speaking of one who lead a children's Bible study at church, another who coached his daughter's softball team, and another victim who took a second job at Walmart because she loved working with people.

He also recalled the words of Aeschulus, a Greek poet, that Robert F. Kennedy used when he broke the the news of Martin Luther King, Jr.’s death to an audience in 1968.

“In our sleep, pain that we cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom through the awful grace of God,” he said.

“Part of what wears on us, what troubles us so deeply is how this senseless violence in the Navy Yard echoes other tragedies,” he said. “You and your families – this Navy family – are still in the early hour of your grief.

"I am here to say there is nothing routine about this tragedy, about your loss. They will endure in the hearts of the American people, in the hearts of the Navy, in the hearts of their coworkers and their friends and their neighbors," said Obama.