Five members of the same family - including three teenage girls - have been arrested in a counter-terrorism probe linked to Syria.
They 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 five - a 51-year-old man, a 53-year-old woman, and girls aged 16, 17 and 19 - were arrested at an address in east London.
They were a husband, wife and their three daughters, according to reports.
Police said the arrests are part of an ongoing inquiry which previously saw the youngest girl arrested last month on suspicion of preparation of terrorism.
It is understood the investigation is linked to Syria and potential plans to travel to the country.
The 16-year-old suspect is currently on police bail to a date in September pending further inquiries in relation to that matter, a Scotland Yard spokesman said.
Officers from the Metropolitan Police's counter-terrorism command attended the address this morning. They were not armed.
In addition, the man was detained on suspicion of possessing false identity documents "with improper intention".
All five are currently in police custody at a central London police station.
Investigative activity by counter-terrorism units is currently at unprecedented levels.
Last week Assistant Commissioner Mark Rowley, the country's most senior terrorism officer, disclosed that suspects are now being arrested at a rate of more than one a day.
Police and security services believe at least 700 potential extremists have travelled to Syria, with around half thought to have returned to the UK.
Several cases have emerged in which women and children are feared to have gone to parts of Syria controlled by the so-called Islamic State.
Scotland Yard confirmed last month it believed more than 40 women and girls had travelled to Syria from Britain in the last year.