President Obama, taking his first trip outside Washington to rally support for new gun measures, stood alongside dozens of uniformed police officers here Monday as he delivered a forceful defense of mandatory background checks for all gun buyers.

Obama also touted his proposed bans on assault weapons and high-capacity ammunition magazines during a speech at the Minneapolis Police Department’s Special Operations Center, signaling his intent to keep pushing for several major policy changes in Congress.

But Obama focused his remarks Monday on his most popular proposal — universal background checks — calling it a “smart” idea rather than a conservative or liberal one. The president sought to drive a wedge between the powerful National Rifle Association, which opposes universal background checks, and the American public, which polls suggest overwhelmingly supports the idea.

Referring to “lobbyists in Washington claiming to speak for gun owners,” Obama said, “We can’t allow those filters to get in the way of common sense. . . . I need everybody who’s listening to keep the pressure on their members of Congress to do the right thing.”

The stagecraft of Obama’s visit Monday, with dozens of police officers and sheriff’s deputies standing behind him, underscored the central role the White House hopes law enforcement officials will play in the political fight for tougher gun laws. The event bore echoes of President Bill Clinton’s successful effort nearly two decades ago to enlist law enforcement support for passage of the 1994 crime bill, which included a 10-year ban on assault rifles that has since expired.

President Obama proposed expansive gun-control policies aimed at curbing gun violence. The Obama administration can implement about half of the proposals, but the others — arguably some of the more critical initiatives — will require congressional approval.

“All the folks standing here behind me today, they’re the ones on the front line of this fight,” Obama said. “They see the awful consequences — the lives lost, the families shattered. They know what works, they know what doesn’t work and they know how to get things done without regard for politics.”

Obama said he would still push to ban military-style assault weapons and ammunition magazines capable of carrying more than 10 rounds, measures that face uncertain prospects on Capitol Hill. A gunman carrying a Bushmaster assault rifle with a 30-round magazine killed 20 children and six adults on Dec. 14 at an elementary school in Newtown, Conn.

“We should restore the ban on military-style assault weapons and a 10-round limit for magazines,” Obama said. “And that deserves a vote in Congress because weapons of war have no place on our streets or in our schools or threatening our law enforcement officers.”

Obama also has called for stricter laws against gun trafficking, a measure that has broader bipartisan support in Congress. “We don’t have to agree on everything to agree it’s time to do something,” Obama said.

On Tuesday, four lawmakers — two Democrats and two Republicans — plan to unveil a bill that would make gun trafficking a federal crime and impose new penalties against gun “straw purchasers” who knowingly buy firearms for convicted criminals who are barred from buying their own weapons.

The four lawmakers — Reps. Patrick Meehan (R-Pa.), Carolyn B. Maloney (D-N.Y.), Scott Rigell (R-Va.) and Elijah E. Cummings (D-Md.) — plan to unveil the measure alongside law enforcement leaders. The lawmakers all hail from urban or suburban areas generally thought to be more supportive of gun regulations.

“We’re going to fight to get this thing on the floor,” Rigell said in an interview with the Washington Post’s Plum Line blog. “This is a great opportunity for our conference to demonstrate and to lead on a very important issue and show the American people we’re ready to do what’s right.”

Separately, Rep. Peter T. King (R-N.Y.) is expected this week to reintroduce two gun-control measures he has sponsored in previous years. The first would bolster efforts to keep firearms out of the hands of suspected terrorists, and the second would ban gun trafficking and broaden efforts to track stolen guns.

Obama’s trip Monday focused on steps that Minneapolis took in recent years to stem an outbreak of gun violence among young people, which Obama said the city had reduced by 40 percent.

Sen. Amy Klobuchar (D-Minn.), who rode on Air Force One with Obama along with Sen. Al Franken (D-Minn.), told reporters that she believes there is strong support in Congress for universal background checks and a ban on high-capacity magazines.

“I thought it was a good beginning, trying to find common ground on the background-check issue,” Klobuchar said, referring to Obama’s appearance. “We just need to give it time, and we need to give it time for the public to think about it. And you see with the numbers on background checks and the high-capacity magazines continue to be strong.”

Klobuchar also supports legislation banning assault weapons but declined to predict an outcome on that issue. “I don’t have a crystal ball,” she said.

Ed O’Keefe in Washington contributed to this report.