A man has been arrested after two alleged attempted carjackings, in which police say two women were assaulted.
Bystanders reportedly used their own cars to block the alleged offender and cut off his escape route, according to a man who spoke to the Sunday Canberra Times but did not want to give his name.
An ACT Policing spokesman said both incidents happened near the Kambah Village Shopping Centre on Marconi Crescent, about 11.30am on Saturday.
"The drivers of the vehicles, a woman in her 40s and a woman in her 60s, were assaulted during these incidents," the spokesman said.
"A man is in police custody and a crime scene has been established."
A witness to the incident saw armed police surround the alleged carjacker while he was still in the vehicle.
One police officer in tactical response gear stood on the bonnet of the car while the situation unfolded.
Officers eventually opened the door and dragged the man from the vehicle and arrested him.
Photos taken at one of the scenes, in the shopping centre car park, showed blood on the ground.
Samantha Walshe, who works in the nearby bakery, said police asked her to give them a bucket of water to clean the blood up.
She said the incidents had caused quite a bit of drama, with customers continuing to chat about what had happened.
Police asked anyone with information on the incidents to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website.
Information can be provided anonymously, quoting reference number 6397571.