(CNN)Two men have been charged in Australia in connection with an alleged plot to bring down a passenger plane, police said Thursday.
Two men charged in Australia over plot to bring down plane
According to a statement from Australian Federal Police (AFP), a 49-year-old man and a 32-year-old man each were charged with two counts of "acts done in preparation for, or planning, a terrorist act."
The maximum penalty for each offense is life in prison.
It comes five days after four people -- including the two men -- were arrested by police over what Prime Minister Malcolm Turnbull described as an "elaborate conspiracy." A 50-year-old man was released without charge on Tuesday. One man remains in custody.
Turnbull said the plot involved bringing down a passenger plane. AFP Commissioner Andrew Colvin said the plan had been to use an "improved device."
No further official details have been released.
Australian media has been full of speculation around the terror plot since the arrests were announced on Saturday. Local newspaper The Australian said the plan involved "an explosive device (creating) poisonous gas."
The AFP would not confirm or deny the report and Minister of Immigration Peter Dutton told media he didn't "want to go into the detail."
Multiple raids have been carried out at multiple properties across Sydney by law enforcement authorities since Saturday, including the suburbs of Surry Hills, Lakemba, Wiley Park and Punchbowl.
Investigators were seen rifling through garbage and removing items from houses, dressed in full protective gear.
Earlier Thursday, Turnbull said the threat to aviation in Australia had been "disrupted and contained" following the arrests and the level of security at airports was being lowered.
Stricter airport security measures had been put in place following the attack, with Australian airports warning of possible delays and longer check-in times.
At the same press conference, Turnbull said a "very substantial" amount of evidence had been uncovered and investigations were ongoing.
The two men facing charges will appears in a Sydney court on Friday morning.