SYDNEY (Reuters) - Australian police are conducting raids across Sydney, officials said on Thursday, though the operation is not related to a cafe siege this week that resulted in the death of two hostages.

Australian Federal Police and New South Wales Police are in the process of raiding properties, a spokeswoman for state enforcement department told Reuters.

While New South Wales Police said details would be provided once the operation was complete, the spokeswoman said the raids were not connected to the Sydney siege on Monday.

The Australian Broadcasting Corporation reported that at least one of the properties raided was targeted during large-scale counter-terrorism raids in September.

Police remain on heightened alert following the deadly hostage siege.

Three people were killed, including hostage-taker Man Haron Monis, when police stormed the cafe early on Tuesday to free hostages held at gunpoint for 16 hours.

Police are investigating whether the two captives were killed by Monis or died in crossfire.