MELBOURNE: Three men who believed Islam was under threat from Western nations were convicted in an Australian court Thursday of plotting a suicide attack against a Sydney army base.

The men — Australian citizens of Somali or Lebanese origin — were convicted in Victoria state Supreme Court of conspiring to plot a terrorist attack, and could face life in prison. Two other men were found not guilty of the same charge.

The five men were arrested in pre-dawn raids in the southern city of Melbourne in 2009.

Police said the group planned to send a team of men with automatic rifles on a suicide attack against Holsworthy Barracks, an army base on the outskirts of Sydney. Officials said the men were motivated by a belief that Islam was under attack from the West, and planned to keep on shooting until they were killed.

During the trial, prosecutors said the men were upset about Australia’s involvement in the wars in Iraq and Afghanistan. Australia became a staunch US ally in the war on terrorism after Sept. 11.

Prosecutors said one of the men visited Somalia in the hopes of gaining approval for the attack from a cleric. The men were accused of having ties to al-Shabab, Somalia’s powerful al Qaeda-linked militia group.

Had the plot been successful, Australian Federal Police Commissioner Tony Negus said it would have been the most serious attack ever carried out in Australia.

Terrorism is extremely rare in Australia, though dozens of Australians have died in terrorist attacks overseas, mostly in Indonesia, including the 2002 Bali nightclub bombings.

The trial began in September and the jury deliberated for more than five days before returning guilty verdicts against Wissam Mahmoud Fattal, 34, Saney Edow Aweys, 27, and Nayef El Sayed, 26.

Abdirahman Mohamud Ahmed, 26, and Yacqub Khayre, 23, were found not guilty.

As jurors left the court following the verdict, Fattal said: ‘‘Islam is truth religion. Thank you very much.’’ Fattal, Aweys and El Sayed embraced their acquitted co-defendants before they were led away.

Outside court, Ahmed told reporters he was relieved.

‘‘I think justice has been served,’’ he said. When asked about the convictions of his co-defendants, he said: ‘‘It’s unfortunate, but this is God’s will.’’

Justice Betty King ordered Fattal, Aweys and El Sayed into custody. They will appear in court again on Jan. 24.