Police say they have foiled an active terror plot after a woman was shot during a raid on a house in Willesden, northwest London.
The woman, in her 20s, was one of the subjects of the investigation and is in a serious but stable condition.
A raid also took place in Kent, with six people arrested in total.
Officers say the operation was not connected to an arrest near Parliament on Thursday, when a man was detained on suspicion on terror offences.
Police said the house in Harlesden Road, Willesden, had been under observation
At about 19:00 BST on Thursday, firearm officers entered the property. CS gas was sprayed and a woman was shot.
A 16-year-old boy, and a man and woman, both aged 20, were arrested. A 43-year-old woman was arrested in Kent.
Two further arrests were made in Willesden after a man and woman, both aged 28, returned to the property.
Deputy Assistant Commissioner of the Metropolitan Police Neil Basu said: "Due to these arrests that have been made yesterday, in both cases I believe that we have contained the threats that they pose."
When asked by reporters whether police had foiled an active terror plot, Basu replied: "Yes."
He added: "There are constant acts of immense bravery by officers, armed and unarmed - those that the public see, where our officers run towards danger just as you saw yesterday, but a huge amount of unseen work that the public will never see behind the scenes."
The Met said the suspects were arrested on suspicion of the commission, preparation and instigation of terrorist acts.
They are in custody at a south London police station.