In breaking news, police have arrested someone at Town Hall station after they were spotted carrying a firearm on a Sydney train.
Officers got on the train at Town Hall just after 12pm, arresting the man.
He is believed to be in his 30s.
Police say that the weapon may have been a replica or a cap gun, and specific details about the nature of the firearm are yet to be confirmed.
Officers from Sydney City Command and Police Transport Command attended the scene.
Taken to Day Street police station and inquiries are continuing.
More to come.