Two Sydney men have been charged with terrorism offences, after a series of raids relating to a potential terrorist attack on Saturday.
Four people were arrested in the raids and one has since been released without charge, with another still in police custody as the investigation continues. He has not yet been charged.
The remaining two, aged 49 and 32, have been charged with terrorism offences and are due to appear in court on Friday morning.
Authorities believe the foiled plot was a plan to poison a planeload of people, with federal police commissioner Andrew Colvin saying: "We think that this was credible and that there was an intention, and there was quite possible a capability as well."
Reports suggest the men were planning to use a poisonous gas on a flight from Sydney to the Middle East, killing hundreds of people on board.
It sparked a series of raids across Sydney where police seized smartphones, tablets, a boarding pass for a recent flight from Indonesia to Sydney, and a meat grinder which could have housed a bomb.
Australian law gives investigators seven days to interrogate those in custody and uncover the plot.
Police say it was an "elaborate conspiracy", rather than a lone-wolf attack.