Four men have been arrested following counter-terror raids across various properties in Sydney on Saturday afternoon, with police revealing an alleged plot to blow up an aircraft.

The arrests were part of a “major counter-terrorism operation” carried out between the NSW Police, the Australian Federal Police and intelligence agency ASIO.

Raids were conducted at properties in Surry HillsLakembaWiley Park and Punchbowl, and per an AFP media release, the four men are currently assisting police with enquiries.

Searches were also conducted to uncover material that might be used to make an improvised explosive device or “some other method” to bring down a domestic passenger flight.

A father and son were reportedly arrested at the Surry Hills property, with several dozen riot squad officers and an explosives team in attendance.

After the raids unfolded, a neighbour told reporters that an older couple with adult children resided at the home, and that they seemed like “perfectly nice and normal people.”

Prime Minister Malcolm Turnbull has made a statement on the raids, saying:

“These operations are designed to disrupt and prevent plans to undertake terrorist attacks in Australia. My number one priority, and that of my government, is the safety and security of all Australians, and the public should be reassured that our security and intelligence agencies are working tirelessly to keep us safe.”

Turnbull is expected to make a further comment later this morning.

It is understood that the raids had been planned for several days, but were brought forward for “operational reasons” in regards to information received.

The AFP says that the broader investigation related to the operation remains ongoing, and that “further information will be made available at the appropriate time.”

They also say that members of the public are urged to follow any instructions they receive from police at or in the vicinity of search locations.

Source: Australian Federal Police
Image: Getty Images / Joosep Martinson