DENVER (AP) -- Ratcheting up pressure for Congress to limit access to guns, President Barack Obama said Wednesday that steps taken recently by Colorado to tighten its gun laws show "there doesn't have to be a conflict" between keeping citizens safe and protecting Second Amendment rights to gun ownership.
"I believe there's no conflict between reconciling these realities," Obama said in Denver, where he was stepping up his call for background checks for all gun purchases and renew his demand that Congress at least vote on banning assault weapons and limiting access to large-capacity ammunition magazines.
"There doesn't have to be a conflict between protecting our citizens and protecting our Second Amendment rights," he said, noting that it's been just over 100 days since the shooting rampage that killed 20 first-graders and six adults at an elementary school in Newtown, Conn., and reignited the national debate over access to guns.
In danger of losing congressional momentum on the issue, Obama went to Colorado - which has a deep-rooted hunting tradition and where gun ownership is a cherished right - to highlight state efforts to tighten gun laws. His intent is to use Colorado's example and public pressure to prod reluctant members of Congress to act.
Colorado recently expanded background checks for gun purchases and placed restrictions on ammunition magazines. Prospects for passage of similar measures by Congress appear bleak, largely because of concerns by conservative Republicans and moderate Democrats who come down more on the side of gun rights.
Obama said there is a middle ground.
"Colorado has shown that practical progress is possible by enacting tougher background checks that won't infringe on the rights of responsible gun owners, but will help keep guns out of the hands of dangerous people," he said.
In Denver, Obama met with 19 law enforcement officers, activists and elected officials at the Denver Police Academy, not far from the Aurora suburb where a gunman last summer killed 12 people in a movie theater. Prosecutors are seeking the death penalty for James Holmes, the accused shooter.
Among those participating in the discussion with Obama was Sandy Phillips, whose 24-year-old daughter, Jessica Redfield Ghawi, died in the Aurora shooting. She conceded that gun control is a difficult issue, and said she has spoken to numerous lawmakers in Washington who "want to do the right thing without it costing their jobs."
Phillips said she is counting on Obama to press the issue.
"We need to have universal background checks for every sale, that's a minimum," she said in an interview before the meeting. "I hope he keeps pushing for the assault weapons ban and I hope he keeps pushing for magazine restrictions."
During a portion of the meeting that was open to the media, Obama said mental health challenges and cracks in the system are contributing factors in deadly mass shootings, along with guns.
He also said there was no doubt about "the kind damage that can be done when you don't have strong background checks, when you have criminals who are easily able to get their hands on weapons that at least in some cases outgun what law enforcement has. ... "We should be able to do something about it in a sensible way."
With Congress due to return to Washington on Monday after a two-week break, Obama has been scheduling high-profile events on gun legislation to push lawmakers and sustain a drive for some kind of action more than three months after the massacre at Sandy Hook Elementary School in Newtown, Conn.
Last week, he called for legislation while flanked by 21 mothers who lost children to gun violence. "I haven't forgotten those kids," he declared then.
The Senate could begin debating gun control legislation next week.
On Monday, Obama was visiting Hartford, Conn., where state lawmakers have announced a bipartisan agreement on gun legislation in response to the Newtown shooting.
White House press secretary Jay Carney said Wednesday that efforts by Colorado and Connecticut "represent important progress on these issues and are useful models to look at as we undertake efforts in Washington."
He said the White House was working with members of Congress and staff from both parties on how to find the necessary votes for passage.
Obama's visit showcased a state with a long centrist tradition that prizes its Western frontier heritage. But an influx of young coastal transplants and growing Hispanic voter clout have helped Democrats win a string of victories in the state. Even before the Sandy Hook massacre energized gun control proponents, Democratic Gov. John Hickenlooper said he was open to new gun control measures.
Colorado Republicans fought the new legislation, contending that Democrats overreached and will be punished by voters in November. Democrats contend that the measures are generally popular, especially among the suburban women who decide Colorado elections.
Several county sheriffs have vowed not to enforce the new gun restrictions. More than a dozen of them gathered a mile from Obama's appearance Wednesday to slam the new regulations as ineffective and unconstitutional.
Justin Smith, the sheriff of Larimer County, dismissed the visit as "a victory lap" and "a slap in the face to all Coloradans."
The Colorado Sheriffs Association vocally opposed the gun control package, while the Colorado Association of Chiefs of Police supported it. Sheriffs are elected in Colorado and generally are Republican.
Several dozen gun supporters booed Obama's motorcade as it arrived at the academy.
Obama's trip comes a day after a study commissioned by the National Rifle Association, which opposes Obama's gun control measures, recommended that schools have trained, armed staffers to increase security for students. The American Federation of Teachers denounced the proposal.
There were signs that sweeping congressional efforts to address gun violence have flagged.
Key senators have been unable to reach a bipartisan compromise that would require federal background checks for gun transactions between private individuals. Federal background checks currently apply only to sales handled by licensed gun dealers.
After Denver, Obama was headed to San Francisco to attend fundraisers Wednesday and Thursday for Democratic Party organizations.
Associated Press writers Nicholas Riccardi in Denver and Alan Fram in Washington contributed to this report.