The mother of Adam Lanza, the gunman who killed 20 children and six adults in one of America’s worst ever school massacres, was a “survivalist” preparing for economic and social collapse, it has emerged.

According to reports, Nancy Lanza was a so-called 'prepper', a part of the survivalist movement which urges individuals to prepare for the breakdown of society by training with weapons and hoarding food and other supplies.

“She prepared for the worst,” her sister-in-law Marsha Lanza told the Chicago Sun-Times.

“Last time we visited her in person, we talked about prepping – are you ready for what could happen down the line, when the economy collapses?”

Marsha Lanza described Nancy as 'self-reliant' and said she repeatedly talked about her preparations for the economic and social meltdown.

It has also emerged that Mrs Lanza had spoken of her fears about her son Adam's behaviour less than a week before the attack.

According to reports she told a friend that she feared "losing" her son", that his state of mind was "getting worse" and that "she was having trouble reaching him".

It has also been reported than Adam Lanza's social awkwardness had caused so much concern at his high school that he was assigned a psychologist.

Police have said Mrs Lanza, 52, owned five legally registered guns, three of which her son carried with him.

Mrs Lanza is thought to have trained her sons, Adam and Ryan to shoot, even taking them to local ranges.

Friends and family have portrayed Mrs Lanza as a paranoid ‘survivalist’ who believed the world was on the brink of violent collapse.

Despite initial reports that she was a kindergarten teacher at the school her son attacked, she had no connection with it and was described by a neighbour as ‘a stay-at-home mom’.

Today's reports come amid growing calls for President Barack Obama to take action over gun controls.

Diane Feinstein, a Democrat Senator, has announced that she will introduce a bill to ban assault weapons when congress opens next month.

New York Mayor, Michael Bloomberg, a known supporter of tighter gun laws, yesterday called on the President to "stand up and lead", in the ongoing debate.

On a visit to Newtown last night, President Obama vowed to use “whatever power” his office holds to prevent “more tragedies likes this.”

As Newtown prepares for the first funerals of victims of the shooting further details emerged about the attack.

According to some reports Adam Lanza killed a complete class of six and seven-year-olds, along with their teacher.