Police in Salt Lake City shot and seriously wounded an autistic child whose mother had called 911 for help when her 13-year-old son started shouting in mental distress.

Linden Cameron suffered from separation anxiety, his mother Golda Barton told reporters, and reacted angrily when she had to return to work for the first time in almost a year.

She called 911 to ask police officers for help in taking the boy to hospital.  

"I told them, 'Look, he's unarmed, he doesn't have anything, he just gets mad and he starts yelling and screaming. He's a kid, he's trying to get attention'," she told local station KUTV.

When the teenager started running from the police, one of the officers opened fire and injured the boy, who is white, with gunshots to the shoulder, intestine, bladder and ankle.  

"During a short foot pursuit, an officer discharged his firearm and hit the subject," police spokesman Keith Horrocks told reporters.

"Given the threats of a weapon, they arrived in the area and made contact with this male, that male fled on foot," Horrocks said.

"He's a small child -- why don't you just tackle him?" his mother said.

According to Horrocks, the boy was suspected of having "made threats to some folks with a weapon."

But he admitted that no weapon had been found so far at the scene of the police shooting.

In a country plunged into protest and division about a string of police killings, the Utah incident provoked strong reaction among local disability advocacy groups. 

"Police were called because help was needed but instead more harm was done," said Neurodiverse Utah in a statement.

The case bore echoes of the death of Daniel Prude, a mentally ill black man whose brother called 911 for help when the 41-year-old was having a psychological breakdown. 

Prude died of suffocation after police put a hood over his head and pinned him to the ground in Rochester, New York in March.