Updated: 21:51

A US CONGRESSWOMAN has been shot point blank in the head and six people have been killed, after a man opened fire at a public meeting in Tuscon, Arizona.

The Guardian reports that Gabrielle Giffords, a 40-year-old Democratic member of the House of Representatives remains in a critical condition in hospital after being was shot at approximately 10am local time as she spoke outside a grocery shop for a constituency event. The attacker has been identified as white male in his late teens or early 20s.

Reuters reports that a total of 18 people were shot in the attack and six people have died, according to Rick Kastigar - an official from the Pima County Sheriff’s Department.

University Medical Center spokeswoman Darci Slaten told Reuters that a nine-year-old girl was among the dead. Federal judge John Roll and an aide to the Congresswoman have also been confirmed dead.

Giffords, a vocal supporter of Obama’s Health Care Reform Bill, had been identified in a “target map” published by former Alaska governor Sarah Palin last year. A total of 20 House Democrats were identified on Palin’s target map, entitled “Its time to take a stand”.

The map and violent rhetoric by Palin’s Political Action Committee was criticised at the time as an “incitement to violence”, particularly after Palin tweeted the map to her followers with the words: “Don’t retreat, instead- RELOAD!”. US website Gawker reports that days after map was introduced, vandals smashed the windows of Giffords Tuscon office.

Giffords’ opponent in the 2010 election was Jesse Kelly, who held an campaign event entitled “Get on Target for Victory in November” – Description: “Help remove Gabrielle Giffords from office. Shoot a fully automatic M16 with Jesse Kelly.”

A motivation for the attack has not yet been identified.

President Obama has called the attack “an unspeakable tragedy”.