Two men have been arrested on suspicion of being members of the Hezbollah terror group.
Detectives arrested a 39-year-old man in north-west London on suspicion of being a member of a proscribed organisation, preparation for acts of terrorism and being involved in a funding arrangement for the purposes of terrorism.
Officers also arrested a 35-year-old man in west London on suspicion of being a member of a proscribed organisation.
The investigation is largely focused on activity overseas, as well as activity within the UK. At this time, there is not believed to be any imminent threat to the public.
Commander Dominic Murphy, head of the Met's Counter Terrorism Command said: "Terrorism and terrorists have a global reach and impact and the activities of terrorist groups overseas can harm communities here in the UK as well as causing devastation to those abroad.
"Our investigation remains ongoing, but I hope that these arrests show we will take robust action against anyone here whom we suspect as being involved in terrorist activity regardless of whether their activity is focused here in the UK or elsewhere."
The two men were taken to a London police station, and have since been released on bail until a date in mid-July.
Searches were carried out at five addresses - two in North West London, one in West London, one in South West London and one in Essex - and these are now complete.
This is a breaking story. More to follow.