A somber Tony Bennett didn't have much to say Wednesday at a press conference on gun violence. But he wanted one message to get through.

"I still haven't gotten over Connecticut," the 86-year-old singer said. "I'd like the assault weapons to go to war, not in our own country. And I'd like assault weapons eliminated. Thank you."

Bennett was one of several celebrities and survivors of shootings who gathered in the nation's capital Wednesday to urge lawmakers to act on firearm legislation--and soon.

Sponsored by the group Mayors Against Illegal Guns, the eclectic group of actors, comedians, advocates and doctors argued for a range of changes, from background checks to all-out bans on assault weapons. The same organization, backed by New York City Mayor Michael Bloomberg, produced a nearly 90-second ad in late December featuring dozens of A-listers calling for a plan against gun violence.

Some simply came Wednesday to throw their support behind President Barack Obama, who's leading a push of his own to tighten gun laws following the Newtown elementary school shooting that left 26 killed, including 20 children.

"The president and the first lady are kind of like the mom and the dad of the country," comedian and actor Chris Rock said. "And when your dad says something, you listen. And when you don't, it usually bites you in the ass later on. So I'm here to support the president."

Obama took his proposals on the road Monday in a campaign-style event in Minneapolis, reiterating his support for banning semi-automatic rifles modeled after military weapons as part of an updated version of an earlier weapons ban that expired in 2004.

A number of proposals have also been put forward on Capitol Hill that would enact stricter gun regulations to varying degrees. Senate Majority Leader Harry Reid said Sunday on ABC that he supported expanding background checks to private transactions--a measure that has widespread, bipartisan support--but stopped short of endorsing an assault weapons ban, as proposed by his Senate colleague Dianne Feinstein.

Opponents say such a ban would do little to prevent gun violence, citing statistics that show most shootings come from handguns, not assault weapons.

Other initiatives that have support from both sides of the aisle include proposals to boost the nation's mental health services. Of the president's 23 executive actions he signed on gun violence last month, three of them deal with mental health and one encourages the Centers for Disease Control to conduct more research on the causes and prevention of gun violence.

Actress Amanda Peet, during the press conference, warned that even with improvements to the mental health system, "a troubled few will slip through the cracks."

"But what's the alternative? Doing nothing will fail, doing nothing has failed," she said.

Kerry Kennedy, whose father Robert F. Kennedy was gunned down in 1968 during his presidential campaign, stood alongside Martin Luther King III, the eldest son of the civil rights activist, at the event.

"We passed the Gun Control Act of 1968 for my father, my uncle, Martin Luther King and Malcolm X," she said, with a photo of her dad on the podium. "Surely we can pass a Gun Control Act of 2013 for the 20 children who lost their lives in Newtown, the school officials who died defending them and all of the Americans who had to die by a gun before we took action."

Dr. Michael Nance, a pediatric and trauma surgeon with the Children's Hospital in Philadelphia, said he frequently operates on children with gunshot wounds.

"Perhaps the most challenging aspect is to look in the eye of a distraught parent and say 'I'm sorry, I've done everything I can do, but it wasn't enough'," he said. "I would urge our legislators to ask the question of themselves regarding gun violence, whether they can look in the face of a parent and say 'I've done everything I can within my power to help'."