A 32-year-old man has been arrested on suspicion of preparation of terrorist acts linked to Syria.
The suspect was held in Brent, north London, on Wednesday by officers from Scotland Yard's Counter-Terrorism Command.
He is being questioned at a police station in central London. Scotland Yard said the arrest is not linked to the investigation into a serviceman who was detained in Somerset.
Scotland Yard said: "Officers from the Metropolitan Police Service Counter Terrorism Command have this morning arrested a 32-year-old man at an address in NW10.
"He has been arrested on suspicion of preparation of terrorist acts - Contrary to Section 5 of The Terrorism Act 2006. He has been taken to a central London police station where he remains pending further inquiries.
"The arrest is linked to Syria."