NEW YORK—Vice President Joe Biden and New York City Mayor Michael Bloomberg issued a joint appeal to members of Congress, urging lawmakers to ignore politics and do the “right thing” by passing new federal gun-control laws.

In an appearance at City Hall, Biden and Bloomberg were joined by family members of some of those killed in December’s mass shootings at Sandy Hook Elementary School in Newtown, Conn., in urging Congress to immediately pass legislation including stricter rules on background checks and a ban on assault weapons, which they both described as “weapons of war.”

“It’s time for the political establishment to show the courage that your daughter showed,” Biden told the father of Lauren Rousseau, a Sandy Hook teacher killed while trying to protect her students.

The vice president signaled the White House wasn’t giving up on its push to ban assault weapons, insisting “this is not about anybody’s constitutional right to own a weapon.”

“For all of those who say we can’t and shouldn’t ban assault weapons, for all those who say the politics is just too hard, how can they say that? When you take a look at those 20 beautiful babies and what happened to them? And those six teachers and administrators?" Biden said. "Think about Newtown. Think about Newtown."

Biden's comments came just days after Senate Democrats dropped an assault weapons ban from their proposed package of gun reforms, arguing it would kill any chance of passing any new gun laws.

Bloomberg, who has emerged as one of the leading voices in favor of new gun-control laws in the aftermath of Newtown, called on lawmakers to have “courage.” He argued that if new gun-control laws don’t pass this year, at least 12,000 people are likely to die from gun violence in 2013 alone, based on past statistics.

“In the end, what Congress has to decide is whether it’s politically popular or is it the right thing to do,” Bloomberg said.

The mayor insisted “there is no debate” among the majority of Americans about the need for tougher background checks and bans on sales of high-capacity magazines and assault rifles.

Story continues

At one point, Biden praised Bloomberg for his advocacy on guns, saying “no support has been more consequential than the support coming from Mayor Bloomberg.”

After Biden and Bloomberg spoke, Neil Heslin, whose 6-year-old son Jesse was killed at Newtown, approached the podium and issued an emotional plea for members of Congress to pass new gun laws.

“I'm really ashamed to see that Congress doesn’t have the guts to make a change,” Heslin said, speaking in a somber tone that was barely audible. “I never thought my son would be a victim. I wish it upon nobody what I have had to go through.”