WASHINGTON (AP) — Vice President Joe Biden said the nation could not wait any longer to respond to gun violence, telling mayors on Thursday that the White House would "take this fight to the halls of Congress."

Biden outlined President Barack Obama's sweeping proposal, announced Wednesday, during a speech to the United States Conference of Mayors, providing a rationale for a plan that includes a ban on assault weapons, the limiting of high-capacity ammunition magazines and requiring background checks for all gun buyers.

Obama's proposal, which is the broadest attempt to tighten gun laws in nearly two decades, faces an uncertain future in Congress, where lawmakers have resisted tougher laws in recent years and some members of Congress have resisted embracing the president's plan. But Biden made clear that the White House would push aggressively for the plan following the deadly school shooting in Newtown, Conn.

"We're going to take this fight to the halls of Congress and we're going to take it beyond that. We're going to take it to the American people. We're going to go around the country making the case," Biden said, vowing that "this time will not be like the times that have come before." Biden said he had "no illusions about the fight that is in front of us" about the challenges of passing the gun control measures but said "we have no choice."

The vice president offered an extensive and detailed explanation of Obama's proposal, which was at the forefront of discussions at the meeting of the national mayor's organization. The group has long supported a ban on assault weapons and other forms of gun control.

Biden urged the mayors to push their state legislatures and governors to make records on gun purchases more available to the federal government and defended efforts to limit high-capacity magazines, saying they "leave victims with no chance" and are "not worth the risk" because the deadly potential in the hands of a criminal.

Responding to calls from the National Rifle Association to have armed guards at schools, Biden says, "We don't want rent-a-cops in schools armed."

Biden's remarks came during the winter meeting of the United States Conference of Mayors, where mayors trade ideas on creating jobs, financing infrastructure projects like water and sewer systems and responding to natural disasters, such as the aftermath of Hurricane Sandy along the East Coast.

During a news conference before Biden's address, mayors said the recent spate of mass murders have brought renewed attention on the issue but it remains one they deal with on a daily basis — a problem that Kansas City, Mo., mayor Sly James likened to "slow-motion mass murder."

Philadelphia Mayor Michael Nutter, the organization's president, said mayors supported the Second Amendment right to bear arms but cautioned that "your right to own a firearm should not interfere with my right to live."

Joe Riley, the mayor of Charleston, S.C., said it was time for Congress to deal with the problem, calling Obama's proposal a "sound, comprehensive, reasonable, common-sense approach that can make our communities safer."

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