They boarded a Turkish Airlines flight, TK1966, which departed at 12:40 to Istanbul, Turkey and landed at 18:40 local time.

They all left before 8am that morning – after providing their families with plausible reasons as to why they would be out for the day. Instead they met and travelled to Gatwick airport.

Officers leading the investigation said they “have reason to believe that they are no longer in Turkey and have crossed into Syria”.

OFFICERS BELIEVE THE three London schoolgirls who fled their homes to join Islamic State militants have crossed the Turkish border into Syria.

Investigating officers say they will continue to work closely with the Turkish authorities on this investigation.

Emotional Appeal

It comes after the families of the schoolgirls appealed for their daughters to come home.

The famiiles of Amira Abase and Shamima Begum after being interviewed by the media at New Scotland Yard, central London Source: Laura Lean

Amira Abase’s family issued a statement saying, ”We want you to come home as soon as possible; all we are hoping for is you to come home safe, we love you so much.

Please come home Amira, everyone is missing you. You are strong, smart, beautiful and we are hoping you will make the right decision.

“We miss you more that you can imagine. We are worried and we want you to think about what you have left behind.”

Kadiza Sultana’s family said, ”In your absence, we, as a family, are feeling completely distressed and cannot make sense of why you left home. Due to the speculation that you may be travelling towards Syria, we are extremely worried about your safety.

We all love you dearly and the last four days have been a complete nightmare not knowing where you are and how you are keeping.

“We would like to emphasise that we are not angry with you and you have not done anything wrong. We just want you all to return home, safe and sound.”

Eldest sister of Shamima Begum, 15, holds her sister's photo while being interviewed by the media at New Scotland Yard, central London Source: Laura Lean

While Shamima Begum’s family said, “We miss you terribly and are extremely worried about you. Please, if you hear this message, get in touch and let us know you are safe. We want you home with us. You belong at home with us.

Syria is a dangerous place and we don’t want you to go there. Get in touch with the police and they will help to bring you home.

“We understand that you have strong feelings and want to help those you believe are suffering in Syria. You can help from home, you don’t have to put yourself in danger. Please don’t cross the border. Please come home to us. Our Mum needs you home and is really worried. We are not mad at you, we love you.”

Girls previously questioned

Police believe the three close friends, who all attend Bethnal Green Academy in east London, are following the example of one of their friends, who fled to join the Islamic State group in December.

The girls were spoken to by officers last December as part of the routine inquiry into the disappearance of their friend.

It’s believed that the three received support in planning the trip, but police do not know the extent of their backing or if they have access to funding.

Source: Bethnal Green Academy via Google Maps

Police have been working with the families and overseas authorities since they were reported missing in an attempt to locate the girls and return them to their families.

Shamina and Amira were reported missing to police by their families later that evening when they did not return home. Kadiza was reported missing by her family on Wednesday morning.

Richard Walton, head of the Metropolitan Police’s Counter Terrorism Command, said, “We are 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 Islamic State.

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.

Anyone with information relating to this investigation is urged to contact the incident room via the free phone Anti-Terrorist Hotline number on 0800 789 321.