CANBERRA, Jan. 18 (Xinhua) -- Four people who were on board a helicopter which crashed enroute to Australia's iconic Uluru have been admitted to hospital.

Northern Territory (NT) Police on Thursday confirmed that the helicopter crashed 1.5 km west of Uluru, the world's largest rock, at 6:00 p.m. local time, just minutes after take-off, on Wednesday.

The helicopter was taking three tourists on a sunset tour of Uluru. The pilot and one of the passengers remained in a serious condition at the Royal Adelaide Hospital on Friday with spinal injuries while the other two were in a stable condition in Alice Springs.

A spokesperson for Alice Springs Hospital said one of the two had sustained multiple broken bones while the other was in hospital as a precaution.

NT Police said that the helicopter crashed in an area that was inaccessible by car and that another helicopter was required to rescue the passengers.

"The helicopter came down hard in scrubland shortly after taking off about 6:00 p.m.," NT Police Duty Superintendent Rob Farmer told reporters on Thursday.

"Another helicopter was able to land and provide immediate assistance.

"Yulara police, fire and rescue services and health staff were notified and attended the scene."

The Australian Transport Safety Bureau (ATSB) said it was aware of the incident but has not yet confirmed if it will investigate the site.

"We've maintained a crime scene at the crash site overnight, pending a decision on the level of further investigation that will be undertaken by the Australia Transport Safety Bureau," Farmer said.

"We're just maintaining the security of that scene until they arrive if they come to do an investigation."