Prime minister: Raids kill plot to crash an aircraft

Anti-terrorism raids carried out across Sydney on Saturday thwarted a plot to bring down an aircraft, Australian Prime Minister Malcolm Turnbull said Sunday.

Turnbull said the “major counterterrorism operation” was ongoing and extra security measures have been put in place at major airports after four people were arrested in the Sydney raids.

Australia, an ally of the United States, has been on heightened alert for attacks by homegrown militants returning from fighting in the Middle East, or their supporters, since 2014.

Authorities say they have thwarted a number of potential attacks since then, but there have been several “lone wolf ” assaults, including a cafe siege in Sydney that left two hostages and the gunman dead.