Perth's Australia Day celebrations have been marred after two people were killed when a stunt plane crashed on the Swan River in front of thousands of people waiting for the city's annual fireworks display.
The seaplane stalled and nose-dived into the water about 5pm, breaking up on impact, as revellers looked on in horror.
Boats rushed to the fixed wing craft in a desperate effort to rescue survivors but police confirmed soon after that both the pilot and sole passenger were dead.
Perth Lord Mayor Lisa Scaffidi immediately announced that the fireworks, scheduled for 8pm, had been cancelled out of respect for those killed and to "conserve the integrity of the crash site".
WA Police acting commissioner Stephen Brown told reporters it was fortunate the plane didn't hit the crowd.
"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," he said.
More than 300,000 people were expected to attend the Skyworks show. However Mr Brown urged those gathered to head home.
Extra public transport services had been organised to help them on their way, he said.
It's not known whether the plane was there as part of the planned festivities.
Earlier in the day, the nation's biggest citizenship ceremony took place in the fast-growing City of Wanneroo in the city's northern suburbs, where 800 residents from 49 countries became Australians.
Debate over whether to change the date of Australia Day meanwhile reached fever pitch in WA, with the City of Fremantle firmly in the crosshairs of some for its bid to move celebrations to January 28.
Others, however, have praised it for trying to get people to think about celebrating nationhood in a more inclusive way.
As they did around the country, "Invasion Day" protesters against marking the First Fleet's January 26 arrival at Botany Bay gathered in Perth's Supreme Court Gardens.
"Today, all around Australia my people are marching," 77-year-old Aboriginal elder Uncle Ben told reporters at the peaceful event.
"We don't want the 26th. That's the day the colonisers arrived here."
After lashing Fremantle council, Premier Colin Barnett said it was time to move on.
"Aboriginal people are now recognised on Australia Day at events throughout our country," he told reporters.
"It means different things to different people but it is our national day and I think we would be foolish as a country to change it."
