Two people have been killed in a horror light plane crash on Perth's Swan River.
The plane was seen flying above the packed Swan River foreshore in preparation for an Australia Day sky show when disaster struck.
Thousands of stunned witnesses watched on in horror as the plane nose-dived into the waterway after 5pm local time on Thursday.
The two victims were a male pilot and his wife.
The plane went down off the South Perth foreshore and appeared to stall and then flip before crashing.
Nearby boaties rushed to the crash scene to assist, and climbed onto the wreckage in a bid to try and save those on board. But sadly, the two people on board could not be saved, with Perth Mayor Lisa Scaffidi confirming the tragic news on Twitter.
"We must sadly advise that there have been two fatalities within the last hour due to a plane crash into the Swan River," she said.
"Due to the operational need to conserve the integrity of the site, in respect for those killed and as per operational directives for such occurrences, we have exercised the option to cancel the Skyshow immediately.
"We hope this message may reach many before they leave home for the event."
Seventeen-year-old Noyonika Chatterjee told The West Australian she watched the crash happen in front of her.
"It just dropped into the water and that was it," she said.
"You could see the parts sticking out of the water. We heard a loud bang and everyone was just shocked. It's such a terrible thing to have happened."
Another witness, Craig Newill, said those around him were just "stunned and shocked".
Western Australia police have confirmed the two people were the only occupants of the aircraft.
Acting commissioner Stephen Brown said it was fortunate the plane didn't hit spectators waiting for the Australia Day festivities to begin.
"For reasons yet unknown, it's entered the waterway, thankfully without injuring anyone else on the ground or any other people who are here at the event."
Pictures from the crash scene show the aircraft split into two on impact, after the plane's wing hit the water first.