Obama urges Congress to pass gun-control legislation 100 days after Newtown

President Barack Obama spoke at the White House with rows of grieving mothers behind him and publicly implored Congress to pass gun-reform legislation 100 days after the Sandy Hook Elementary School mass shootings in Newtown, Conn.

"We've cried enough. We've known enough heartbreak. ... It's something that if we are serious, we will do," Obama said, Vice President Joe Biden at his side. "Now is the time to turn that heartbreak into something real."

As the mothers of children killed by gun violence wiped away tears, the president went on to urge the passage of background checks for gun buyers, and for loopholes to be closed for buyers who turn around and sell guns to criminals. He said 90 percent of Americans support background checks, as well as 80 percent of gun owners and 80 percent of Republicans.

Obama also suggested that too much time has passed since the shootings at Newtown. "Shame on us if we've forgotten. I haven't forgotten those kids. Shame on us if we've forgotten," the president said.

Later on Thursday, at the White Press briefing, Principal Deputy Press Secretary Josh Earnest addressed questions regarding timing and whether the president himself has acted swiftly enough on gun reform: "The president, I think, has been very forward-leaning in terms of the way he's engaged in this process."

Earnest also noted the 23 executive actions released by the White House in January and the more than 20 events and conversations with lawmakers, community leaders, survivors and gun-related groups the White House has undertaken in the days since Newtown.

But what many consider to be the most contentious proposed gun-reform legislation, an assault weapons ban, was absent from the president's remarks on Thursday.

Senate Democrats working on gun-reform legislation recently announced that they would drop an assault weapons ban from an overall package of reform measures and put it to a separate vote as an amendment. That action is designed to boost the chances a reform package will pass, as it's expected that the ban is too unpalatable for some members, especially Democrats in gun rights states and the multitude of Republican opponents.

The White House has been casting a positive spin on that decision, suggesting that offering the ban as an amendment still forces lawmakers to choose sides on the issue, even if it doesn't win passage.

"I can't stand here and guarantee that it’s going to pass," Earnest said at Wednesday's press briefing, "but it is a question that 100 senators are going to ask themselves when they wake up in the morning and look themselves in the mirror about whether or not they are going to—about which side they're going to be on when it comes to voting on a ban on military-style assault weapons." He added that the president will continue to advocate for the ban.

Democrats in Congress concede separating the ban from the overall package is the best way forward.

"We want to come out with the best, the boldest common denominator that we can get," House Minority Leader Nancy Pelosi said at a news conference on Wednesday when asked about the decision to separate an assault weapons ban.

Senate Majority Leader Harry Reid has stated plans to introduce a gun-reform bill next month.

In addition to the president's talk, activities related to gun reform are taking place across the country on Thursday, a day gun-reform advocates have marked the "National Day to Demand Action" to end gun violence.

New York City Mayor Michael Bloomberg’s anti-gun group, Mayors Against Illegal Guns, released two television ads on Thursday featuring family members of those killed in Newtown.

Court documents released on Thursday revealed, among other things, that police investigating the Sandy Hook massacre seized samurai swords, as well as a massive amount of ammunition and books on guns and mental health from the home of gunman Adam Lanza.