Security at Sydney Airport has been ramped up. Credit:Michele Mossop Authorities uncovered this after Khaled Merhi, Khaled Khayat and Mahmoud Khayat were arrested in counter-terrorism raids across Sydney on Saturday evening. They were detained over an alleged and pending plot to smuggle an improvised explosive device on to an Etihad flight departing Sydney for Abu Dhabi. On Thursday night, the Australian Federal Police charged Mahmoud Khayat, 32, and Khaled Mahmoud Khayat, 49, each with two counts of acting in preparation for or planning a terrorist act. Both men are scheduled to appear in Parramatta Court on Friday morning. The maximum penalty each could face is life imprisonment.

Khaled Khayat, pictured at Sydney Airport in 2014, is one of the men arrested. Khaled Merhi remains in custody. His brother, Abdul Merhi, 50, was released from police custody without charge on Tuesday night. For the past several days, police have been scouring through the Surry Hills, Lakemba, Punchbowl, Bankstown and Wiley Park homes of the four men, who are related through marriage. NSW Police Commissioner Mick Fuller. Credit:Daniel Munoz A meat mincer, which would either explode or disperse deadly gas, was the suspected weapon. It is understood it was among the items seized from the Surry Hills terrace.

Since police turned their focus to the alleged plotters last week, investigators uncovered information about the alleged earlier attempt that got as far as the airport terminal. Police examine items outside Khaled Khayat's Lakemba unit as part of their investigation into an alleged terrorism plot. Credit:AAP It is unclear when the close call occurred, although it was before police launched their investigation into the Sydney men last week. Multiple sources have confirmed the earlier attempt but said that, even if the device did make it past the airline check-in, it might have been detected in a security screening. Police at the scene of the terrorism raid in Surry Hills Credit:Brook Mitchell

NSW Police Commissioner Mick Fuller said on Thursday there had been a lot of speculation about what the alleged attack entailed, but added that police stopped what could had been a "horrible crime". "Terrorism is very different to other crimes; you cannot wait until you have the perfect brief, you cannot wait until you have all the pieces of the puzzle because you cannot afford to let the criminal act happen," he said. The scene of a terrorism raid in Surry Hills. Credit:Brook Mitchell "When we go early to protect the community, it gives us an opportunity to make sure we gather all the necessary evidence." Security measures at Australia's major airports were heightened last week after police received information about the alleged bomb threat.

Khaled Khayat allegedly took a bomb back home to Lakemba after it was too heavy to be checked in on an Etihad flight. The move prompted lengthy passenger queues that snaked outside terminal doors as travellers were urged to arrive hours before their flights. However, following advice from ASIO that there was no longer an active threat to the aviation industry, some security measures would be eased, Mr Turnbull said. Five properties in Surry Hills, Punchbowl, Wiley Park and Lakemba were raided as part of a counter-terrorism operation in Sydney. Credit:Channel Nine News People should follow the directions of their airline, he added.

"There will be continued enhanced security measures. Some of them will be visible to travellers, some of them will not," he said. It is understood that British and US spies fed information about the alleged bomb plot to their Australian counterparts. That came after communication was intercepted between members of the alleged Sydney terrorist cell and Islamic State operatives in Syria. Police then launched the dramatic counter-terrorism raids on Saturday evening. Investigators are now looking closely at the background and associations of those involved, who were little more than a blip on the terrorism radar before last week.

Khaled and Abdul Merhi are understood to be related to Ahmed Merhi, who was once viewed as an active recruiter for IS in Syria, where he has been based since 2014. However Abdul Merhi's lawyer, Moustafa Kheir, said it was "unfathomable" his client would be associated with such a terrorist plot. "A lot of information was divulged, including his identity," he said on Wednesday. Loading "That's caused a lot of damage to him. We want to review all the information police had and what basis they had to do what they did."

Abu Dhabi-based Etihad Airways, the group's alleged target, issued a statement on Tuesday saying it was helping police with the investigation.