WASHINGTON, D.C. (CBS 5 / KCBS / AP) — Braced for a fight, President Barack Obama on Wednesday unveiled the most sweeping proposals for curbing gun violence in two decades, pressing a reluctant Congress to pass universal background checks and bans on military-style assault weapons and high-capacity ammunition magazines like the ones used in the Newtown, Conn., school shooting.

A CBS 5 poll of Bay Area residents – taken shortly after the president released his plan – showed significant support for background checks (76%), an assault weapons ban (71%), and ammunition limits (67%).

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U.S. House Minority Leader Nancy Pelosi (D-San Francisco) was also quick to embrace Obama’s plan – although Republican House Speaker John Boehner was non-committal to the president’s package and signaled no urgency to act on the legislative proposals.

“Congress must do its part, without further delay, to strengthen background checks and take the most dangerous weapons and assault magazines out of the hands of those in greatest danger of doing harm to themselves and to others,” Pelosi said in a statement to CBS San Francisco. “For the families of the victims of Sandy Hook, of every massacre and every incident of gun violence, there is simply no time to waste.”

A month after that horrific massacre, Obama also used his presidential powers to enact 23 measures that don’t require the backing of lawmakers. The president’s executive actions include ordering federal agencies to make more data available for background checks, appointing a director of the Bureau of Alcohol, Tobacco, Firearms and Explosives, and directing the Centers for Disease Control to research gun violence.

But the president, speaking at White House ceremony, focused his attention on the divided Congress, saying only lawmakers could enact the most effective measures for preventing more mass shootings.

“To make a real and lasting difference, Congress must act,” Obama said. “And Congress must act soon.”

San Francisco Mayor Ed Lee was heading to Washington for the U.S. Conference of Mayors as he parsed through Obama’s executive order, and said that he would have to answer several questions like if San Francisco has the resources to do extensive background checks on all gun buyers and whether police can get armor-piercing bullets off the streets.

“If we use data better and link it up to the kinds of purposes that we want, we’ll have better information on who is buying guns, who’s responsible for these things,” Lee said. “And I’m looking forward to maybe technology answering some of the challenges that we have – maybe having guns that are only usable by the owners with their hand prints.”

Lee said part of his job in Washington this week will be to get together with other mayors and present a united front to get Congressional action on some of the tougher gun control recommendations.

The president vowed to use “whatever weight this office holds” to press lawmakers into action on his $500 million plan. He is also calling for improvements in school safety, including putting 1,000 police officers in schools and bolstering mental health care by training more health professionals to deal with young people who may be at risk.

Pro-gun groups in California promptly took issue with Obama’s proposals, and even supportive lawmakers acknowledged the president’s gun control measures may face long odds in Congress.

Napa Congressman Mike Thompson, who chairs the House Gun Violence Prevention Task Force, and said he would review the president’s ideas and then propose a comprehensive set of his own.

“We’re trying to figure out what the best package will be to make our communities safe, protect people and still allow people to have and use their firearms for appropriate purposes,” Thompson said.

Thompson joined Pelosi for a hearing after the president’s announcement, to hear from Newtown families and others involved in the debate.

Brandon Combs, executive director of the Cal Guns Foundation and spokesman for four other pro-gun groups in California, said he doubts an assault weapons ban or 10-bullet limit will ever become law.

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“I would encourage California gun owners to remain vigilant and cautiously approach any sort of nuance in these proposals because we’re just going to have to wait and see,” Combs said. “The enforcement is going to be where these things present constitutional questions.”

Acknowledging the tough fight ahead, Obama said there will be pundits, politicians and special interest groups that will seek to “gin up fear” that the White House wants to take away the right to own a gun.

“Behind the scenes, they’ll do everything they can to block any commonsense reform and make sure nothing changes whatsoever,” he said. “The only way we will be able to change is if their audience, their constituents, their membership says this time must be different, that this time we must do something to protect our communities and our kids.”

The president was flanked by children who wrote him letters about gun violence in the weeks following the Newtown shooting. Families of those killed in the massacre, as well as survivors of the shooting, were also in the audience, along with law enforcement officers and congressional lawmakers.

“This is our first task as a society, keeping our children safe,” Obama said. “This is how we will be judged.”

Seeking to expand the impetus for addressing gun violence beyond the Newtown shooting, the president said more than 900 Americans have been killed by guns in the month since the elementary school massacre.

“Every day we wait, the number will keep growing,” he said.

The White House has signaled that Obama could launch a campaign to boost public support for his proposals, as national polls mirror the CBS 5 poll in the Bay Area showing that a clear majority Americans want stricter gun laws in the aftermath of the Newtown shooting.

The president based his proposals on recommendations from an administration-wide task force led by Vice President Joe Biden. His plan marks the most comprehensive effort to address gun violence since Congress passed the 1994 ban on high-grade, military-style assault weapons. The ban expired in 2004, and Obama wants lawmakers to renew and expand it.

Other measures Obama wants Congress to take up include limiting high-capacity ammunition magazines and requiring background checks for all gun buyers in an attempt to close the so-called “gun-show loophole” that allows people to buy guns at trade shows and over the Internet without submitting to background checks.

Obama also intends to seek confirmation for B. Todd Jones, who has served as acting director of the Bureau of Alcohol, Tobacco, Firearms and Explosives since 2011.

The president’s plan does little to address violent images in video games, movies and entertainment, beyond asking the CDC to study their impact on gun crimes. Some pro-gun lawmakers who are open to addressing stricter arms legislation have insisted they would do so only in tandem with recommendations for addressing violence in entertainment.

The president’s long list of executive orders also include:

– Ordering tougher penalties for people who lie on background checks and requiring federal agencies to make relevant data available to the federal background check system.

– Ending limits that make it more difficult for the government to research gun violence, such as gathering data on guns that fall into criminal hands.

– Requiring federal law enforcement to trace guns recovered in criminal investigations.

– Giving schools flexibility to use federal grant money to improve school safety, such as by hiring school resource officers.

– Giving communities grants to institute programs to keep guns away from people who shouldn’t have them.

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