190427 Mohamed Noor
Mohammad Noor Image Credit: AFP

Washington: A former US police officer on trial for fatally shooting an Australian woman told a Minneapolis court Friday that he fired to protect his partner, but never saw a gun - only a blonde woman in a pink T-shirt with her right arm raised.

At issue in the trial of Mohammad Noor, the 33-year-old officer who killed Justine Damond in the Midwestern city in July 2017, is whether the use of deadly force was justified.

"I had to make a split-second decision to protect my partner," Noor said in testimony that began Thursday.

He said he believed there was an imminent threat after he saw a cyclist stop near their police cruiser, heard a loud bang and saw partner Matthew Harrity's "reaction to the person on the driver's side raising her right arm."

Noor added when he reached from the cruiser's passenger seat and shot Damond, 40, through the driver's side window, it was because he thought his partner "would have been killed."

He said that after Damond aapproached the cruiser, his partner screamed "Oh, Jesus!" and began fumbling to unholster his gun.

"I fired once, she took a couple of steps back and was falling to the ground," Noor said, describing how Harrity immediately began exiting the cruiser.

Determining that he had "stopped the threat", Noor said, he also got out, holstered his gun and joined Harrity in assisting Damond as she fell.

Damond, a yoga instructor, had approached the cruiser after calling twice to report a possible rape in the dark alley behind her home. No such assault was ever found to have occurred.

She had moved to the Midwestern city to marry her American fiancee Don Damond. She had changed her name from her maiden name.

Closing arguments are expected next week in the month-long trial.