Officers from the Metropolitan Police Service's Counter Terrorism Command [SO15] attended a residential address in east London, at approximately 08.15hrs, on Thursday, 16 June, and arrested a 15-year-old boy on suspicion of encouraging terrorism contrary to section 1 of the Terrorism Act 2006.
Officers are searching the address.
The boy has been taken to an east London police station where he remains in custody pending further enquiries.
The arrest has been under PACE.