Australia warned that another terrorist attack was expected in Saudi Arabia and urged its citizens Thursday to avoid traveling to the kingdom.

The government also authorized the voluntary departure of families of Australian embassy staff from Riyadh (search), the Saudi capital, a statement said.

"There is new information suggesting that further terrorist attacks in Saudi Arabia may be in the final stages of planning," the Department of Foreign Affairs and Trade said in its latest travel advisory, without elaborating.

"In view of continuing tensions in the Middle East and the ongoing risk of terrorist attacks against Western interests ... Australians should defer nonessential travel to Saudi Arabia," it said.

It also said Australians in Saudi Arabia who are concerned for their safety should consider leaving.

On May 12, car bombings of three Western housing compounds in Riyadh killed 26 people and the nine assailants.

Saudi Arabia has cracked down on Islamic militants in highly publicized raids after the suicide attacks. Authorities there announced on Monday the arrests of a number of terrorist suspects and the discovery of large quantities of weapons and ammunition during raids around the kingdom.