LONDON - British police said Monday they have arrested four women in the past two days over a terror plot foiled in London last week, including one shot by counter-terrorism officers during a raid.

A total of 10 people are now in custody in connection with the investigation, which escalated on Thursday evening when armed police forced their way into a house in Harlesden, north London, using tear gas and opening fire.

Two 18-year-old women and a 19-year-old woman were arrested on Monday morning in east London on suspicion of the commission, preparation and instigation of terrorist acts, the Metropolitan Police said in a statement.

On Sunday, the 21-year-old woman who was shot during the raid on Thursday was also arrested after being discharged from hospital. Police said the Harlesden property had been under surveillance as part of an ongoing counter-terrorism operation. They confirmed it was an active plot.

A judge this weekend agreed to extend the custody arrangements of the first six people arrested in the case.

The three women and three men - one of them a 16-year-old boy - can now be held until Thursday at the latest.

All of the suspects are accused of the same charges of allegedly commissioning, preparing and instigating terrorist acts.

The Harlesden raid came just hours after the unrelated arrest of a man near the Houses of Parliament on suspicion of terrorism offences and the possession of knives.

Deputy Assistant Police Commissioner Neil Basu said there was an "increased level of terrorist activity" but said it was being matched by police action, with near daily arrests.