ISIS terrorist (illustration)
ISIS terrorist (illustration) Reuters

Three missing schoolgirls who left Britain to join the Islamic State (ISIS) terrorist group have crossed into Syria and are believed to be staying at a house in the city of Raqqa, Sky News reported on Sunday.

The three - Shamima Begum, 15, Kadiza Sultana, 16, and Amira Abase, 15 - boarded a flight from Gatwick Airport bound for Istanbul last month.

Authorities feared the teenagers were seeking to join the Islamist terrorists. According to the Sky News report, the girls are now in a house that is owned or controlled by a British girl who had been in contact with them through the internet, and had brought them through Turkey and into Syria.

"We are told by... good sources within the city of Raqqa that they are there, that they are safe. That is where they are staying - with this British girl who is hosting them,” Sky's Stuart Ramsay said.

Last week, CCTV footage emerged which appeared to show the three teenagers at a bus station in Istanbul.

In the footage, the girls were seen wrapped in heavy winter jackets, two with hoods pulled up, and carrying packed sports bags and holdalls.

The footage was recorded in the early hours of February 18, less than 24 hours after the trio left their London homes, telling their families they would be out for the day.

Turkey, which has been accused by its Western allies of failing to do enough to stop jihadists crossing into Syria from its territory, has accused Britain of failing to provide information about the girls sooner.

Scotland Yard said it had informed the Turkish embassy in London the day after the girls disappeared and said the Turkish authorities had since provided "great assistance".

Turkey’s Deputy Prime Minister, Bulent Arinc, claimed however that Britain had failed to take the "necessary measures" and that it "should have informed us and shared intelligence with us". 

Arinc's complaints echoed similar remarks made by Turkish officials after Hayat Boumeddiene, the wanted partner of one of the gunmen behind the January terror attacks in France, traveled undetected through Turkey on her way to Syria.

In that case, Ankara accused the French authorities of failing to share information in a timely manner about the wanted woman's departure for Turkey.