A New York man with a history of psychiatric problems decapitated his mother, dragged her body into the street in front of their home and then killed himself by walking in front of an oncoming train, Long Island police said yesterday.

The defence contractor who fatally shot 12 people at the Washington Navy Yard was carrying three weapons during the rampage.

A gunman who opened fire inside a US navy base in Washington, killing 12 people, was a full-time reservist from 2007 to 2011.

At least 12 people have died in a shooting rampage at a US navy yard in Washington DC, police said.