Detectives from the Met Police Counter Terrorism Command, assisted by officers from Sussex Police arrested three men at approximately 18:00hrs on Friday, 30 June on suspicion of the commission, preparation or instigation of acts of terrorism.
The men - aged [A] 28, [B] 31, arrested separately in Essex and [C] 28 arrested in East Sussex - are being held in custody under the Terrorism Act in a south London police station.
Detectives have also executed search warrants at one residential address in East Sussex, and three residential addresses in east London.
All searches have now been completed.
Enquiries are ongoing.