A married couple and their three daughters have been arrested in east London on suspicion of Syria-related terrorism offences.
A 51-year-old man, two women aged 53 and 19, and two girls aged 17 and 16, who are understood to live in Tower Hamlets, were held on suspicion of possessing information likely to be useful to a person committing or preparing an act of terrorism, Scotland Yard said.
The force said the arrests were part of an ongoing investigation – the 16-year-old girl was previously arrested on 2 July on suspicion of preparation of terrorism. At that time she was released on police bail to a date in September.
At the time of her first arrest, when she was 15, she was believed to be the youngest girl ever to be held over a terrorism offence.
The man was also held on suspicion of possessing false identity documents with improper intention. All five were in custody at a central London police station.
It is understood the investigation is linked to Syria and potential plans to travel to the country. Militant extremists from Islamic State now control large parts of the conflict-torn country and have lured supporters from across Europe to their cause.
Police and security services believe at least 700 potential extremists have travelled to Syria, with around half thought to have returned to the UK.
Assistant commissioner Mark Rowley, the country’s most senior counter-terrorism officer, last week disclosed that suspects were being arrested at a rate of more than one a day.
Rowley also revealed at least 32 children in London had been made the subject of family court orders this year over fears of radicalisation – include some described by the assistant commissioner as “almost babes in arms”.
In the first official count of female jihadis thought to be in Syria, police last month said 43 women and girls were feared to have fled to the country in the past year.
Among them were three sisters from Bradford, who ran away with their nine children, and a family of 12 from Luton who disappeared earlier this month.
School friends Shamima Begum and Amira Abase, both 15, and Kadiza Sultana, 16, all from Bethnal Green, east London, left for Syria in February. Some are now thought to be married to Isis extremists.