Four men were arrested over an alleged plot to attack a commercial airliner in Sydney, Australia.
The men reportedly planned on using poisonous gas, released in the cabin, to kill hundreds of people on board.
Another theory is a bomb was to be hidden inside a meat mincer, which police have seized, and taken on board.
The men believed to be taking instructions from Islamic State militants in Syria.
Counter-terrorism officers were reportedly only made aware of the four men when they got a call from an overseas authority last week.
It can also be revealed that a homemade bomb ‘ready to go’ was discovered following the arrest of four men following Saturday’s raids across Sydney.
The other two men were arrested in Western Sydney, one in Lakemba dressed only in a towel
This, police say, an alleged plan to smuggle home made explosive devices on board a long haul flight to the Middle East, possibly Dubai, and blow it up.
“You can’t wait until you put the whole puzzle together. You have to go early because if you get it wrong the consequences are severe.
Federal Police Commissioner Andrew Colvin said the threat had to be taken seriously.
Following the incident, Airports across Australia has tightened the security checks and a result long line up to get to the passport control and to reach departure gates.