WASHINGTON (AP) ― President Barack Obama promised on Wednesday to send Congress broad proposals in January for tightening gun laws and curbing violence, declaring the time for action overdue after last week’s massacre of children at a Connecticut school.

Even before those proposals are drafted, Obama pressed lawmakers to reinstate a ban on military-style assault weapons, close loopholes that allow gun buyers to skirt background checks and restrict high-capacity ammunition clips.

“The fact that this problem is complex can no longer be an excuse for doing nothing,” Obama said in his most detailed comments on guns since Friday’s killing of 20 schoolchildren and six adults in Newtown, Connecticut. “The fact that we can’t prevent every act of violence doesn’t mean we can’t steadily reduce the violence.”

Gun control measures have faced fierce resistance in Congress for years but that may be changing now because of last week’s violence. Since then, Obama has signaled for the first time in his presidency that he’s willing to spend political capital on the issue and some prominent gun-rights advocates in Congress ― Democrats and Republicans alike ― have expressed willingness to consider new measures.

Still, given the long history of opposition to tighter gun laws, there is no certainty the legislation Obama backed Wednesday or the proposals he will send to Congress next month will become law.

Many Americans consider arms ownership a cherished freedom and have been outspoken in their opposition to tighter gun laws.

The Arizona Citizens Defense League, a group that advocates for pro-gun state legislation, said Wednesday that guns should be allowed in Arizona public schools to provide protection against shootings such as the one in Connecticut. Some conservative politicians elsewhere in the country have echoed that view.

Obama tasked Vice President Joe Biden, a longtime gun control advocate, with overseeing the administration-wide process to create those proposals. Beyond firearms’ restrictions, officials will also look for ways to increase mental health resources and consider steps to keep society from glamorizing guns and violence.

Obama’s January deadline underscores the desire among White House officials to respond swiftly to the Newtown shooting. Obama aides worry that as the shock of the shooting fades, so, too, will the prospects that pro-gun lawmakers will work with the White House to tighten restrictions.

“I would hope that our memories aren’t so short that what we saw in Newtown isn’t lingering with us, that we don’t remain passionate about it only a month later,” said Obama.

In Newtown, mourners overlapped at back-to-back funerals that started Monday and will continue all week. A 7-year-old boy who had dreamed of being a firefighter and a heroic first-grade teacher who died while trying to shield students from the carnage were among latest victims laid to rest.

And in what has become a dark rite of passage in America, survivors of a 2005 school shooting that killed 10, including the gunman, on an Indian reservation in Minnesota traveled to Connecticut to offer comfort to the community. They said they sought to repay the support they received nearly eight years ago from survivors of the 1999 Columbine High School killings in Colorado, which left 15 dead, including the two gunmen.

Emphasizing the need to take action, Obama said eight people have been killed by guns across the U.S. since the Newtown shooting. Among them were a 4-year-old boy and three law enforcement officers.

The president has called for a national dialogue on gun violence before, after other mass shootings during his presidency. But his rhetoric has not been backed up with concrete action. And some of the gun measures Obama has signed lessened restrictions on guns, allowing people to carry concealed weapons in national parks and in checked bags on Amtrak trains.

The president bristled at suggestions that he had been silent on gun issues during his four years in office. But he acknowledged that the Newtown shooting had been “a wake-up call for all of us.”

The shooting appears to have had a similar impact on several longtime gun backers in Congress. West Virginia Sen. Joe Manchin, a conservative Democrat and avid hunter, has said “everything should be on the table” as Washington looks to prevent another tragedy, as has 10-term House Republican Jack Kingston of Georgia.

There was little response from Republicans Wednesday following Obama’s statements. New York City Mayor Michael Bloomberg, an independent who has been sharply critical of the president’s lack of action on gun issues, called the effort a step in the right direction.

Obama, seeking to ease the fears of gun owners, reiterated his support for the Second Amendment of the Constitution, which gives citizens the right to bear arms. And he said no effort to reduce gun violence would be successful without their participation.

“I am also betting that the majority, the vast majority, of responsible law-abiding gun owners would be some of the first to say that we should be able to keep an irresponsible, law-breaking few from buying a weapon of war,” he said.

He also challenged the National Rifle Association to do “some self-reflection.” The gun lobby is a powerful political force, particularly in Republican primaries, and previously has worked to unseat lawmakers who back gun control measures.

The NRA, in its first statements since the shooting, pledged Tuesday to offer “meaningful contributions to help make sure this never happens again.”

The Biden-led task force will also explore ways to improve mental health resources and address ways to create a culture that doesn’t promote violence. The departments of Justice, Education, Health and Human Services, and Homeland Security, along with outside groups and lawmakers, will all be part of the process.

Biden will start his discussions Thursday when he meets with law enforcement officers from around the country.

The vice president’s prominent role could be an asset for the White House in getting gun legislation through Congress. Biden spent decades in the Senate and has been called on by Obama before to use his long-standing relationships with lawmakers to build support for White House measures.

The vice president also brings to the effort a long history of working on gun control issues, having chaired the Senate Judiciary Committee and leading the original effort to ban assault weapons. The ban expired in 2004, but Sen. Dianne Feinstein, a Democrat, says she plans to bring it back for a vote early next year.