CALGARY — An air ambulance flew a three-year-old boy to hospital after he caught his arm in a riding lawn mower north of Calgary.

The child was riding the lawn mower near the town of Olds, Alta., on Tuesday morning when he fell and caught his arm in the machine, said Cameron Heke, a spokesman for the air ambulance company STARS.

The child was flown to Alberta Children's in serious but stable condition.

"He sustained a limb-threatening injury," Heke said.