NEW YORK (AFP) - Families of the victims of the Sandy Hook school massacre three years ago have been awarded US$1.5 million (S$2.1 million) in damages from the estate of the shooter's mother, their lawyers' office said on Wednesday (Dec 23).

Twenty children and six educators were killed when Adam Lanza went on a deadly rampage at the elementary school in Newtown, Connecticut on Dec 14, 2012.

US media reported that eight separate lawsuits, involving 16 plaintiffs, were filed seeking compensation from the estate of Ms Nancy Lanza, who was fatally shot by her son Adam moments before the massacre.

He went on to commit suicide.

"There was a settlement for the amount of 1.5 million" dollars, Ms Ana Rios, assistant to lawyer Joshua Koskoff who is representing nine of the families involved, told AFP.

The lawsuits accused Ms Lanza of negligence for leaving a rifle unguarded in her home, within the reach of her son, who had a history of mental illness, media reported.

The authorities in Newtown last March demolished the Lanzas' house in a residential part of town, after neighbours complained that it was triggering painful memories of the massacre.

Sandy Hook elementary was knocked down in 2013, making way for a new school that is set to be inaugurated next year.

President Barack Obama vowed on the anniversary of the massacre not to give up on vexed efforts to tighten US gun laws, assailing the Republican-controlled Congress for failing to pass reforms tightening background checks on gun buyers.