Australia Halts 'Terror Plot'

Australian authorities say they have stopped a terrorist plot to bring down a passenger plane.

In raids across Sydney, counter-terrorism officers said they had seized materials that could have been used to make an improvised explosive device.

Australian Prime Minister Malcolm Turnbull said the raids had been "a major joint counter-terrorism operation."

He also said extra security was in place at domestic and international airports.

Police did not provide details of the target. 

Four men have been arrested.