President Obama on Monday began the first serious push of his administration to attempt to reduce gun violence, directing Cabinet members to begin formulating a set of proposals that could include an effort to reinstate a ban on assault rifles.

The effort will be led by Vice President Biden, according to two people outside government who have spoken to senior administration officials since Friday, when a gunman rampaged through Sandy Hook Elementary School in Newtown, Conn., killing 20 children, six adults and himself.

The initial steps ended a paralyzing debate within the administration over how hard to pursue gun-control legislation, which in the past has proven to be a politically perilous issue for many Democrats.

On Capitol Hill, there were signs Monday that such fear was abating among key Democrats, although leading Republicans remained largely silent on what steps might be necessary to curb gun violence.

Senate Majority Leader Harry Reid (D-Nev.), Joe Manchin (D-WV), and Mark Warner (D-Va.) made clear that Congress should consider a range of options to address the issue; all three have been strong supporters of gun rights. Sen. Dianne Feinstein (D-Calif.) said she would introduce legislation that would reimpose the assault rifle ban that lapsed in 2004.

Majority sees Connecticut shooting as societal problem

“We need to accept the reality that we’re not doing enough to protect our citizens,’’ Reid said after a moment of silence on the Senate floor. “In the coming days and weeks we’ll engage in a meaningful conversation and proper debate about how to change laws and culture that allow this violence to continue to grow...And every idea should be on the table.’’

“I’ve been a strong supporter of Second Amendment rights,” Warner said Monday outside the Virginia Capitol, where he was attending an unrelated meeting. “I’ve got an A rating from the NRA. But the status quo isn’t acceptable. I’ve got three daughters.”

“They asked me on Friday evening, ‘Dad, what are you gonna do about this?’ ” Warner added. “There’s got to be a way to put reasonable restrictions, particularly as we look at assault weapons, as we look at these fast clips of ammunition.”

Warner said his resolve to pursue a solution solidified over the weekend while attending a Washington Wizards game. Many people approached him to talk about the tragedy, in which a gunman with a military-style rifle killed 20 first-graders and seven adults.

“I must have had a half-dozen people come up — Colin Powell, actually,” Warner said. “People were just coming up and saying, ‘Hey, we’ve got to [do something].’ ”

Manchin, a conservative Democrat and National Rifle Association member, told MSNBC that the massacre of 20 children and seven adults made clear the need to consider new regulations on such weapons. Two other adults were wounded in the shooting and are recovering.

“I don’t know anyone in the sporting or hunting arena that goes out with an assault rifle,” Manchin said on “Morning Joe” on Monday. “I don’t know anyone that needs 30 rounds in a clip to go hunting.”

Manchin personifies the group of lawmakers who in the past have blocked efforts to impose stronger regulations on gun ownership. He got an A rating and an endorsement from the NRA in both the 2010 special election and 2012 general election for his seat. In a memorable campaign ad, he shot a copy of a cap-and-trade bill with a rifle.

But on Monday, he said the schoolhouse massacre “changed the dialogue, and it should move beyond dialogue. We need action.” The gun lobby, he said, should be part of that conversation.

“Never before have we seen our babies slaughtered,” Manchin said. “Anybody that’s a proud gun owner, anybody that’s a proud member of the NRA, we’re also proud parents. We’re also proud grandparents.”

In several places around the country Monday, police responded to threats — or perceived threats — at schools. The Associated Press reported that in Ridgefield, Conn., swarms of parents picked up their children at schools after a report of a suspicious person at a nearby train station.

Near Philadelphia, officers rushed to a high school after security officers mistook a student’s umbrella for a gun. And in Tampa, Fla., the Hillsborough County sheriff’s office questioned students after a bullet was found on a school bus.

And in Los Angeles, police said Monday that they had arrested a man and seized nine guns after he allegedly made threats on social media. Kyle Bangayan, 24, of Pomona was booked into the downtown jail Sunday for investigation of making criminal threats, police Cmdr. Andrew Smith told the AP. He remained in jail with bail set at $500,000.

Police and FBI agents went to the east Hollywood home of Bangayan’s father after a resident notified authorities about the threatening postings that referred to the deadly school shootings in Connecticut, Smith said.

“When we get information like this, we take it very seriously, even more so now in light of the Connecticut school shootings,” Smith told the AP.

Also Monday, a new Washington Post-ABC News poll showed that more than half of Americans see the massacre at Sandy Hook Elementary School last Friday as a sign of broader problems in society, not merely the isolated act of a troubled individual.

The finding reverses a recent trend in which the public saw mass shootings in Tucson and Aurora, Colo., as aberrations that did not reflect underlying problems in American culture.

But The Washington Post poll did not show a significant shift in public opinion on the gun issue itself. A clear majority of Americans continues to support a nationwide ban on high-capacity ammunition clips — the kind used at Sandy Hook last week, and in other recent high-profile killings. Just over half support banning semiautomatic handguns. At the same time, nearly three out of four Americans continue to oppose banning the sale of all handguns except to law enforcement officers.

Sen. Dianne Feinstein (D-Calif.) has vowed to introduce legislation to ban assault weapons at the start of the next Congress. Retiring Sen. Joseph Lieberman (I-Conn.) has also called for reinstating the ban, which expired in 2004.

In Newtown, a picturesque town about an hour north of New York City, classes at all seven schools were canceled Monday. Teachers were meeting at the high school to prepare for the return Tuesday of students from all schools except Sandy Hook.

The kindergarten-through-fourth-grade school that was targeted will be closed indefinitely, Newtown’s school superintendent said, to allow families time to grieve and give administrators a chance to figure out how best to proceed.

The first funerals — for victims Noah Pozner and Jack Pinto — took place Monday afternoon. Later, there will be a wake for James Mattioli, according to a list of burial arrangements compiled by the Connecticut Funeral Directors Association. All three boys were 6 years old.

State police Lt. Paul Vance told reporters that police continue to scour both the Sandy Hook school building and the home of gunman Adam Lanza. They are looking for evidence that will help them understand why Lanza allegedly killed his mother, Nancy Lanza, at home, then went to the school and gunned down 20 children and six adult staff members before taking his own life.

“We’re going to hold those locations until we’ve completed our work,” Vance said. “Every single round of ammunition will be looked at for any kind of physical evidence.”

Vance said two adults who were shot and wounded in the rampage are recovering from their injuries. He did not identify those victims or give details.

Police were investigating several potential threats that had been received regarding local churches and schools Monday. Two schools in nearby jurisdictions were locked down briefly while police investigated and cleared reports of possible threats.

“We’re all obviously on edge,” Vance said. “Anything that appears to be any breach of security, or a possible breach of security, will be treated very, very seriously.”

He said investigators are eager to speak to anyone who knew or treated Lanza, and to find out everything they can about him. So far, little is known except that he was very bright and socially awkward.