Sydney, Aug 7 (IANS): Police in the Australian state of New South Wales charged a third man in the terror plot to bring down a plane on Sunday, after last week's raids saw two men charged with terrorism related offences.

Khaled Merhi, 39, was charged with possessing a prohibited weapon but police have yet to say whether the charges against Merhi were related directly to the charges levelled against brothers Khaled and Marmout Karyat, who faced court last week on terror charges, Xinhua news agency reports.

After being held in police custody for eight days following the raids conducted across Sydney, Merhi was released from custody late on Sunday. He is scheduled to appear in court over the firearms charges later this month.

The Karyat brothers have been charged with what the Australian Federal Police allege was one of the "most sophisticated terror plots attempted on Australian soil" and said it involved two aspects.

The first was the alleged attempt to plant an improvised explosive device (IED), disguised as a meat grinder, within luggage on a plane, while the second allegedly involved deploying a gas bomb in a public area.

According to police, the IED itself was a "high-end military grade explosive". The plans were allegedly foiled when the men attempted to take the luggage on the flight but were allegedly turned away at the check-in counter as the bag with the device was found too heavy to place on board.

Police say the bomb was then dismantled and the second alleged plot to unleash a hydrogen sulphide bomb in a public area was then hatched by the plotters. But at the time of the raids, the authorities were adamant that the gas device was nowhere near completion.