HOW THE PLOT WAS FOUND AND FOILED

What was the plot?

The group allegedly planned to use an improvised device to bring down an aeroplane in an Islamist- inspired conspiracy, however police say they have limited information so far about the date, location or specific strategy involved.

What happened during the raids?

NSW and Federal Police swooped on five properties in the Sydney suburbs of Surry Hills, Lakemba, Wiley Park and Punchbowl on Saturday afternoon and found a “considerable” amount of material.

But police won’t say if they discovered an actual explosive device.

Who is in custody?

Four men were arrested and are assisting with police inquiries. No details have been released about their age, background or relationships to one another.

Could it have happened?

AFP Commissioner Andrew Colvin said it treated the plot as credible and there was an intention and “quite possibly a capability” to carry it out. But he also said there was no reason to believe security at Australian airports has been jeopardised.

What happens now?

The arrested men haven’t yet been charged. Police say searches at four of the properties are ongoing and could take “many more days” as they gather enough evidence to support charges.

What’s changing at airports?

Travellers have been told to arrive two hours earlier to make allowances for increased scrutiny. They may notice “intensified” security procedures, but some will happen behind the scenes. Travellers have also been asked to limit baggage.