US Vice President Joe Biden said he would get the results of his probe into curbing gun violence to President Barack Obama by Tuesday, as the response to the Newtown school massacre gathers pace.

As he met officials from sporting and hunting groups Thursday, Biden hinted that his ideas could include new restrictions on the use of high capacity ammunition magazines and more comprehensive background checks for gun buyers.

Later, the vice president was due to meet gun lobby groups, including the National Rifle Association (NRA), which opposes reforms like the reinstatement of an assault weapons ban and has called for armed guards in all US schools.

"There is no conclusion that I have reached. I am putting together a series of recommendations for the president that he will take a look at," Biden told reporters before his meeting.

"I have committed to him I will have these recommendations to him by Tuesday," Biden said.

Obama gave Biden until late January to come up with policy ideas after attending a moving vigil for the 20 children and six adults killed by a gunman spraying bullets from an assault rifle in Newtown, Connecticut on December 14.

On Wednesday, before meeting advocates of victims of gun violence, Biden suggested that Obama could issue some executive orders to tackle the issue, as well as send top priority legislation to Capitol Hill.

Biden, involved in law enforcement issues for years as a senator, said that he had been impressed by calls from all stakeholders in the gun debate for more comprehensive background checks to be required for gun owners.

He also said that there was a growing movement in Congress, even from pro-gun lawmakers, for restrictions on high capacity magazines which can fire off multiple rounds at defenseless victims in a matter of seconds.

The vice president's meeting, including Attorney General Eric Holder and Interior Secretary Ken Salazar, also grouped hunting groups like Ducks Unlimited and Pheasants Forever.

Later, Holder was holding talks with retailers who sell guns, including officials from giant chains Wal-Mart and Dick's Sporting Goods.

Biden and other top administration officials have also met mental health advocates in a bid to work out how to make it more difficult for disturbed people to get firearms.

Later, he will meet officials from the video gaming and entertainment industry, amid concerns that violent content could also play a role in inspiring massacres like recent outrages in Newtown and Aurora, Colorado.