Anxious parents are buying armoured backpacks for children and firearms enthusiasts are stocking up on semi-automatic rifles in anticipation of tighter gun control measures following the Connecticut school massacre.

While a spike in gun sales is common after a mass shooting, the latest rampage in Newtown has generated record sales in some states, particularly of assault weapons.

Colorado set a single-day record for gun background check requests the day after the shootings, while Nevada saw more background checks in the two days that followed than any other weekend this year. Records were also set in several states.

After Friday's Connecticut shooting, Ken Larson and his wife decided to buy their one-year-old son an armoured backpack just to be safe. Mr Larson already owns one which he takes to cinemas.

"It's a no-brainer. My son's life is invaluable," said Mr Larson, 41, of Denver, Colorado. "If I can get him a backpack for 200 dollars that makes him safer, I don't even have to think about that."

Many gun-sellers declined to comment this week, citing a perceived bias in the media and fear of being singled out by law enforcement, but firearms instructor Greg Taggart said most were out buying the weapons "because they can".

The 54-year-old gun-owner from Plano, Texas, said three days before then-president Bill Clinton's 1994 ban on new sales took effect, he bought one of his two AR-15 type assault rifles, similar to the one the Newtown gunman used last Friday in an attack on Sandy Hook Elementary School that killed 26 people, including 20 children.

The ban expired in 2004 and a similar ban is being considered in Congress again.

"There was a serious concern that I wouldn't be able to get one in the future," Mr Taggart said yesterday. "I, as a law-abiding citizen, was morally insulted" by the previous ban, he added.

Some gun shop owners stopped selling remaining stocks of assault weapons, anticipating only more interest and value after President Barack Obama ordered his administration to create concrete proposals to reduce gun violence.

Robert Akers, a South Dakota gun seller who specialises in military-style weapons, said the rush of customers had transformed his Rapid Fire Firearms store into a "madhouse" and that he was not actively selling the guns.

"The price is only going to go up higher," he said.

There was also an unusual increase in sales for the armoured backpacks, designed to shield children caught in shootings, according to three companies that make them.

The armour inserts fit into the back panel of a child's backpack, and sell for up to 400 dollars (£247). It is designed to stop bullets from handguns, not assault weapons like the one used in the shooting at the Connecticut school.

Some experts, however, say sending children to school in armoured backpacks is not a healthy response to fear about mass shootings. Anne Marie Albano, psychiatry director at Columbia University's Clinic for Anxiety and Related Disorders, said parents should convey calmness, not anxiety.

"This is not serving to keep children safe," she said. "This is serving to increase their fear and their suspicion of their peers."

Kerry Clark, president of Texas-based Backpackshield.com, began making the backpacks after the deadly mass shooting at Virginia Tech in 2007. He said he sold 15 backpacks on Wednesday. Before Friday's shooting, he said, the company would sometimes go an entire month with one sale.

Sales of assault weapons also were on the rise.

Austin Cook, general manager of Hoover Tactical Firearms in Alabama, said the increase in sales since Friday's shootings has been so intense that government background checks that typically take five minutes or less are now taking up to an hour.

He said said about 50 people were waiting in line for his store to open the morning after the shootings and he had since sold nearly all of his assault weapons.

But chain store Dick's Sporting Goods said it was suspending sales of modern rifles nationwide because of the shooting. The company is also removing all guns from display at its store closest to Newtown.

Meanwhile President Obama will observe a moment of silence at the White House today to remember the victims of the Connecticut massacre.

The White House said the president's observance of the shootings would take place in private without press coverage.

A private funeral has been held in New Hampshire for the woman whose son shot her dead at their Connecticut home then drove to Sandy Hook School and killed 20 children.

Donald Briggs, the police chief in Kingston said the funeral for Nancy Lanza was held yesterday at an undisclosed location.

He said about 25 family members attended the ceremony in the small town, where Mrs Lanza once lived.

Her 20-year-old son Adam killed her at their home in Newtown last week and then drove to the school, where he killed the children and six staff before committing suicide.

The Newtown massacre is the second-worst school shooting in US history after the 2007 Virginia Tech rampage, which left 33 people dead.