Australia terror probe: Plane suspects 'made two plots'

Australian police have stepped up their presence at the nation's airports

Two men accused of a plotting to put a bomb on a plane were also trying to build a device that could release toxic gas, Australian police have alleged.

The men, aided by the so-called Islamic State (IS), failed in a bid to smuggle an explosive on to an Etihad flight in Sydney on 15 July, authorities say . They also allegedly plotted to build a gas "dispersion" device, but police said it was far from being realised.

Investigators said the alleged plots had been "completely disrupted". "This is one of the most sophisticated plots that has ever been attempted on Australian soil," said Australian Federal Police (AFP) Deputy Commissioner Michael Phelan.

What is claimed about the 'bomb plot'?

Mr Phelan said a "high-end" military-grade explosive had been concealed in luggage and taken to Sydney Airport on 15 July, but it did not get through check-in.

"There is a bit of conjecture [about] why it did not get through the baggage check-in, but I want to make it quite clear - it never got near [security] screening," he said.

Police allege one of the suspects was put in contact with a senior IS figure in April. The IS figure arranged for the components of the device to be sent to Australia from Turkey via air cargo, Mr Phelan said.

Police allege the accused men assembled the parts into a "fully functioning" improvised explosive device.