U.S. President Barack Obama has announced plans for a new gun control initiative, saying he has tasked Vice-President Joe Biden with coming up with a set of proposals to restrict access to automatic weapons such as the one used in last week's school shooting that left 28 people dead.

Obama said he expects Biden -- a longtime gun control advocate -- to work with a team of people from both sides of the political spectrum before presenting proposals by the end of January.

"Their task is going to be to sift through every good idea that's out there -- and even take a look at some bad ideas before disposing of them -- and come up with a concrete set of recommendations in about a month," said Obama, speaking from the White House. "I would hope 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 a month later."

Obama said he plans to push legislation "without delay" following the report from Biden's team, and urged Congress to hold votes on the new law next year.

The debate over gun control has been simmering in the U.S. since last Friday, when lone gunman Adam Lanza opened fire on Sandy Hook Elementary School, killing 20 children and six adults, before turning a gun on himself. He is also believed to have shot his own mother at their family home before embarking on the shooting rampage.

Police have said 20-year-old Lanza was armed with two handguns and a military-style assault rifle, which were legally registered to his mother, Nancy Lanza.

Obama said Wednesday that most Americans believe high-powered assault weapons and high-capacity ammunition clips should be restricted, and that guns shouldn't be sold without background checks first being performed.

"If we work harder to keep guns out of the hands of dangerous people, there would be fewer tragedies like the one in Newtown," Obama said, adding 10,000 Americans die every year as the result of gun violence.

Obama also acknowledged that gun control is a deeply divisive issue in the United States, saying viewpoints differ drastically from rural to urban areas on what is acceptable.

But just because the issue is complicated, doesn't mean it shouldn't be addressed, he said. "The fact this problem is complex can no longer be an excuse for doing nothing."

Obama also called on Americans, especially gun-owners, to support the initiative, saying their support could determine the success or failure of proposals that could directly reduce violence in the U.S.

"The fact is the vast majority of gun-owners in America are responsible," Obama said. "They buy their guns legally and use them safely, whether for hunting or sport shooting, collection or protection. But you know what? I am also betting the vast majority of law-abiding gun owners would be some of the first to say we should be able to keep an irresponsible, law-breaking few from buying a weapon of war."

The tragedy last week in Newtown, Conn. has prompted several congressional gun-rights supporters to consider new legislation to control firearms. But there are also concerns that their willingness to participate could fade as time passes.

The largest and most powerful advocate for U.S. gun-ownership, the National Rifle Association, broke its silence Tuesday after a four-day media blackout in the wake the shooting. In a statement, the NRA pledged "to help to make sure this never happens again" and has scheduled a news conference for Friday.

Obama said the NRA comprises many mothers and fathers and urged them to remember the pain caused by last week's violence.

While the U.S. president welcomed the NRA’s support, he said: "This time words need to lead to action."