Another person has been arrested in east London in connection with a counter-terrorism operation.
Metropolitan police arrested a woman at a property in Hackney early on Saturday.
She is being held on suspicion of the commission, preparation or instigation of acts of terrorism.
Six other people were arrested on Thursday morning as part of the same investigation.
The BBC reports eight houses in west, east and north London and one business premises have been searched.
Metropolitan police said the operation is not connected with the Olympics or Paralympics.