Failed terror plot may have involved bomb or gas: Aus media

Four men arrested by Australian police were allegedly planning to bring down a plane by using poisonous gas or a crude bomb, media reports said today, with Prime Minister Malcolm Turnbull calling their preparations "advanced".
The suspects - identified as Lebanese-Australians - were arrested in raids across Sydney on Saturday evening. The detectives were still scouring the properties in Surry Hills, Lakemba, Wiley Park and Punchbowl that were raided earlier.
According to media reports, the plot could have involved an improvised bomb inside a meat grinder or poisonous gas on a plane.
The men allegedly planned to carry the device on board a commercial flight from Sydney to a Middle East destination as hand luggage, The Sydney Daily Telegraph reported.

Prime Minister Turnbull today said that the plans were "advance" but refused to give any details of the plot.
"I can't say precisely how far they were advanced at this stage, because that's a matter that's being investigated. But I can say that certainly the police will allege they had the intent and were developing the capability," he said.

He said that it was the 13th terrorist plot that has been disrupted by Australian agencies since 2014.
Citing its sources, the Australian newspaper said it was a "non-traditional" device that could have emitted a toxic sulphur-based gas and would have killed or immobilised everyone on the plane.

An Australian Broadcasting Corporation report identified the apparent instigator of the alleged plot as Khaled Khayat, whose brother is believed to be a senior IS fighter in Syria.
Khaled Khayat's son, Mahmoud Kayat, was also being held by police while the other two men arrested, Abdul El Karim and Khaled Merhi are related to Ahmed Merhi, who travelled to Syria in 2014 and was fighting for IS.
"I don't want to go into the detail but...There was a significant threat that federal police, ASIO, NSW police and other agencies dealt with and are in the process of dealing with," Border Protection Minister Peter Dutton said today.

A magistrate on Sunday granted police an additional period of detention which will allow authorities to keep the four suspects for another a week without charge.
The ABC report said the tip off came from intelligence agency in US and UK which intercepted communications to the conspirators from Syria.
The Daily Telegraph claimed that an Etihad flight to Abu Dhabi was the target of the alleged plot and it involved using a gas substance rather than explosives, which was harder for airport security to detect than a kilo of explosives.
Security has been beefed up at all major domestic and international airports following the arrest of four men. The screening at all major Australian airports has been ramped up and air travellers have been warned to expect delays.