The lawyer for a man accused of the shocking and brutal murder of an eight-year-old boy from a Chasidic Jewish community in New York has claimed his client was pushed into confessing to the crime.

Levi Aron, who admitted to killing Leiby Kletzky in July after the boy's dismembered body parts were found in a suitcase and at Aron's home, appeared at a court hearing in Brooklyn on Monday.

After confessing to the kidnap and murder Aron, a hardware shop worker, pleaded not guilty. He underwent a psychiatric assessment after he was charged and was declared competent to stand trial.

Aron's lawyer Howard Greenberg said he did not believe the confession was valid. "This guy would admit he shot Kennedy if you spent enough time with him," he said, adding that he believed that the authorities had told Aron what to write.

His lawyers are expected to defend Aron on the basis that he is not guilty by reason of insanity. Mr Greenberg said: "Anyone who thirsts for blood can take solace in the fact that he will spend the rest of his life in an asylum, never to see the light of day."

Dov Hikind, a state assemblyman for Borough Park, where the Kletzky family live, said a not guilty verdict would "stab a knife into the family".

Aron is set to appear in court for the next hearing on December 21.