WASHINGTON: President Barack Obama pledged Monday to vigorously pursue "sensible" gun control but, a month after a school massacre traumatized America, questioned whether tough new laws could pass Congress.

Grieving relatives of some of the 20 children gunned down in their classes in Newtown, Connecticut on December 14, meanwhile vowed there should never be a "next time" and added heartbreaking heft to the fight against gun violence.

Obama said that Vice President Joe Biden had delivered "common sense" reform recommendations after meeting gun control advocates, firearms lobby groups, mental health experts and software and movie industry officials.

The president said he would lay out his response to the American people later in the week, but backed a renewal of a ban on assault weapons, curbs on high capacity magazines and better-enforced background checks for gun owners.

"My starting point is not to worry about the politics. My starting point is to focus on what makes sense, what works. What should we be doing to make sure that our children are safe?" Obama said at a White House press conference.

He called on members of Congress, many of whom oppose greater gun control legislation, to examine their consciences over whether the carnage at an elementary school in Newtown should prompt a new approach.

Obama said he would "vigorously pursue" gun control measures early in his second term, both through legislation and executive actions, but left some ambiguity over prospects for reform in a polarized political environment.

"Will all of them get through this Congress? I don't know," Obama said.

David Keene, president of the top gun rights group the National Rifle Association (NRA) told CNN Sunday that an assault weapons ban was unlikely to make it through Congress.

The NRA opposes most of the White House's likely proposals, and has instead called for armed guards at every US school.

In Newtown, bereaved parents marked the one-month milestone of the day when gunman Adam Lanza went on a rampage with a fast firing semi-automatic rifle, killing 20 small children at Sandy Hook Elementary School and six adults.

Nicole Hockley, whose son Dylan was among the six- and seven-year olds who perished, said: "I do not want someone sharing my experience and (to be) consoling another parent next time.

"I do not want a next time."

Nelba Marquez-Greene, mother of dead six-year-old Ana, promised to turn the tragedy into a moment of "true transformation."

"I put two children on the bus and only one came home," she said.

New York City Mayor and gun control campaigner Michael Bloomberg told a gun safety summit in Baltimore on Monday that improved vetting of prospective gun owners was simply "common sense."

"We have laws on the books that require background checks when dealers sell guns. It's time for the president and Congress to make that the law of the land for all sales," he said.

In his news conference, marking the end this week of his first term, Obama put a surge in sales of weapons -- including assault rifles and ammunition -- down to a fear of new legislation.

But he insisted that responsible gun owners had nothing to fear from the government and said he backed the right to bear arms enshrined in the Second Amendment to the US Constitution.

"Those who oppose any common sense gun control or gun safety measures have a pretty effective way of ginning up fear on the part of gun owners that somehow the federal government's about to take all your guns away," he said.

"It obviously is good for business."

Biden met an NRA representative along with other gun rights groups last week as part of his gun policy review. He also met with victim support groups, and mental health and law enforcement specialists.

He also looked into the idea that violent content in video games and movies could spur disturbed people to carry out appalling acts.

As the White House readies a rollout of his ideas, the vice president sat down Monday with Democratic lawmakers, as he seeks to plot a route through Congress for the reforms.

The Newtown tragedy may prove a catalyst for a new push for gun control, after little was done following earlier mass shootings in Colorado, Wisconsin and Arizona, and a daily rash of killings in US inner cities.

A new ABC News/Washington Post poll meanwhile found most Americans support banning assault weapons and high-capacity ammunition magazines.

The poll found high support for some shifts: 88 percent favor background checks on buyers at gun shows; 76 percent urge checks on buyers of ammunition; 71 percent back the creation of a new federal database to track all gun sales; and 65 percent back banning high-capacity ammunition magazines.