The Department of Homeland Security said Sunday it is closely monitoring the foiled Australia terrorist plot in which extremists planned an attack targeting an airplane.

“We are closely following the terrorism investigation in Australia and assisting our partners," DHS said in a statement.

"The Department of Homeland Security remains focused on the persistent and emerging threats to aviation, and we have taken extraordinary steps in recent weeks to raise the baseline of aviation security worldwide, especially to protect flights bound for the United States," the statement said. "We will continue to work with authorities in Australia and elsewhere to confront these threats.”

ADVERTISEMENT

Australian Prime Minister Malcolm Turnbull said Saturday that Australian authorities had thwarted a terrorist plan to "bring down" an airplane through counterterrorism raids.

Authorities arrested four men in connection with the plot, The Australian reported.

While those arrested have not been charged, authorities believe the attack was inspired by the Islamic State, Australian Federal Police Commissioner Andrew Colvin said.

While Australian authorities know the aviation industry was a target, they are still investigating details of the planned attack such as when and where the individuals intended to carry it out.

“However, we are investigating information indicating that the aviation industry was potentially a target of that attack," Colvin said, according to the Australian publication.

Australia's justice minister, Michael Keenan, said this plot serves as a reminder that lone wolf attacks are not the only serious threat to their country.

"There is still the ability for people to have sophisticated plots and sophisticated attacks remain a real threat," he said.