Scotland Yard is appealing for information about three teenage schoolgirls who are believed to be trying to make their way to Isis-controlled territories in Syria.
Shamima Begum, 15, possibly travelling under the name of Aklima Begum and Kadiza Sultana, 16, are missing along with a 15-year-old girl who is not being named at the request of her family.
All three girls left their homes at 8am on Tuesday morning and met at Gatwick Airport, where they boarded a Turkish Airlines flight to Istanbul.
Detectives from the Metropolitan Police urgently appealed for information about the missing girls, who all go to the Bethnal Green Academy school and were described as "straight-A students".
Counter Terrorism Command (SO15) Commander Richard Walton said: “We are extremely concerned for the safety of these young girls and would urge anyone with information to come forward and speak to police. Our priority is the safe return of these girls to their families.
"We are reaching out to the girls using the Turkish media and social media in the hope that Shamima, Kadiza and their friend hear our messages, hear our concerns for their safety and have the courage to return now, back to their families who are so worried about them."
Commander Walton said he was concerned “about the numbers of girls and young women who have or are intending to travel to the part of Syria that is controlled by the terrorist group calling themselves Isis”.
He said the girls are good friends with another 15-year-old who ran away to Syria in recent months.
“It is an extremely dangerous place and we have seen reports of what life is like for them and how restricted their lives become. It is not uncommon for girls or women to be prevented from being allowed out of their houses or if allowed out, only when accompanied by a guardian.
“The choice of returning home from Syria is often taken away from those under the control of Islamic State, leaving their families in the UK devastated and with very few options to secure their safe return."
Shamima and the unidentified girl were reported missing by their families on Tuesday night. Kadiza was reported missing on Wednesday morning.
Shamina is described as 5''7" tall, and wearing black thick rimmed glasses, a black hijab, light brown and black leopard print scarf, dark red jumper, black trousers and jacket.
Kadiza is described as 5'6" tall, of slim build and wearing black rimmed glasses, a long black jacket with a hood, grey striped scarf, grey jumper, dark red trousers, carrying a black holdall.
The third missing girl is described as 5'6" tall, of slim build, wearing black thick rimmed glasses, black head scarf, long dark green jacket with fur lined hood, light yellow long sleeved top, black trousers, white trainers carrying a black Nike holdall.
Anyone with information on their whereabouts is asked to call the incident room via the free phone Anti-Terrorist Hotline number on 0800 789 321.