American police have released 911 tapes of emergency services responding to the Arizona shooting incident as it unfolded.

The audio tapes define the key moments on the day the US Representative Gabrielle Giffords was attacked.

Emergency services can be heard urgently relaying first word of the shooting rampage in Tucson, Arizona.

In the recordings of the attempted assassination a dispatcher can be heard saying, "a caller's reporting a shooting, a semiautomatic weapon. He shot at people."

He then adds, "we have a caller who believes that Gabrielle Giffords was shot. That's multiple victims."

As the incident progressed the dispatcher says, "customers have tackled the suspect. They are holding him down."

Realising the magnitude of the shooting he is overheard saying, "We have at least seven, eight...maybe ten gunshot wounds here....and I believe Gabrielle Giffords is here."

He then says: "there are multiple victims"

Three-term Democrat, Giffords, was hosting a community outreach event when she was shot in a Tucson shopping centre parking lot, which left six others dead. Up to 11 others were wounded at the shooting.

According to law enforcement officials the gunman Jared Lee Loughner, 22, shot her in the head after working his way down a line of people waiting to talk with her.

The attack ended when bystanders tacked Loughner. He is currently in custody.

Doctors have recently revealed that Giffords has made strong progress toward recovery. The 41-year-old Democrat is moving both legs and both arms, has opened her eyes and is responding to friends and family. They have also helped her to sit up.