A victim of last week's Arizona gun attack has been arrested and ordered to undergo a mental evaluation after threatening a Tea Party leader during the taping of a television show.

James Eric Fuller, 63, who was shot in the knee on 8 January, objected to comments from Trent Humphries, leader of the conservative Tea Party political movement in Tucson, during taping of a town hall meeting organised for an ABC News special programme on the aftermath of the shootings.

Mr Fuller stood, turned and snapped a picture of Humphries, said Pima County Sheriff's Department spokesman Jason Ogan.

‘Then he yelled at him and said, 'You're dead',’ Mr Ogan said.

Deputies arrested Mr Fuller on charges of disorderly conduct and making a threat.

After consultation with a doctor, deputies then took Mr Fuller to a local hospital for an involuntary evaluation, Mr Ogan said.

The charges will be filed with the Pima County Attorney's Office, he said.

James Eric Fuller was one of 13 people injured when a gunman opened fire during a gathering of constituents of US congresswoman Gabrielle Giffords.

Six people died, including a federal judge and a nine-year-old girl, and the Democratic congresswoman remains in critical condition in a Tucson hospital.

A 22-year-old college dropout, Jared Lee Loughner, was arrested for the shootings. He has been charged with five federal counts, including the murder of a federal judge and the attempted assassination of Ms Giffords.

The rampage sparked a national debate about whether the vitriolic tone of partisan politics in the US in recent years had contributed to the suspect's motivations.