A man has been arrested Tuesday on suspicion of terrorism offences as part of an investigation by the London Metropolitan Police (Met)'s Counter Terrorism Command.
The 20-year-old man was arrested at an address in west London under section 41 (1) of the Terrorism Act 2000 and was taken to a south London police station where he remains in police custody, said the Met.
Officers are also carrying out a search at the address in west London and enquiries continue.
The Scotland Yard said this arrest is not connected to the investigation into suspicious explosive packages received at three buildings in London earlier on Tuesday.
The packages - all A4-sized white postal bags containing yellow Jiffy bags - have been assessed by specialist officers to be small improvised explosive devices.