SYDNEY - A Sydney zookeeper has been injured and is in a critical condition after being crushed by a young elephant during a training session at Taronga Zoo, local media reported Friday.

The incident occurred in the zoo's elephant barn just before 11:30 am local time on Friday when the young male elephant pinned the zookeeper against a bollard.

The female zookeeper, in her 40s, was unconscious and not breathing when paramedics arrived at the scene.

She was taken to the Royal North Shore Hospital with severe chest injuries.

"Two other keepers in an adjoining stall responded to her call and moved the elephant away," Tarango Zoo said in a statement.

"The zoo is waiting for confirmation about her condition from the hospital."

An investigation into the incident is underway.

"It's unknown at this time why the young elephant challenged the keeper," the zoo said in the statement.