Counter-terror raids in Sydney's southwest Photo: ABC
A plot to bring down a plane in Australia using an improvised device has been foiled, after raids in Sydney yesterday.
Four people are in custody after raids on five properties, and searches will continue for days yet.
No date or location for the alleged attack is known, but it's believed an improvised device was seized during the raids.
"This is an example of the outstanding work that is conducted by the Joint Counter-Terrorism team," says PM Malcolm Turnbull.
"The number one priority of my government and my commitment to the Australian people is to keep them safe."
Security was stepped up at Sydney airport on Thursday and the same now applies at all major domestic and international airports around the country. Passengers are being told to arrive two hours before their flights, and try to limit their luggage, to help with delays to security processing.
Justice Minister Michael Keenan says it's a reminder to be vigilant.
"The primary threat to Australia still remains lone actors. But the events overnight remind us there is still the ability for people to have sophisticated plots. Sophisticated attacks still remain a real threat," he says.
"If there's something you see that's suspicious, something that's not right, call the national security hotline on 1800 123 400."