ISTANBUL

Istanbul security sources have released video showing the movements of three British teenage girls who passed through Turkey en route to Syria to allegedly join extremist rebels.

Video acquired by Istanbul's security directorate on Monday showed the trio at a major bus station in the city on 17 Feb.

The recording shows that three British teenagers came to the Istanbul bus terminal with their luggage and left from there to travel to Sanliurfa, a southeastern province of Turkey adjacent to Syria. The three girls had spent the night in the bus terminal before travelling south on a coach.

The students – Shamima Begum, 15, Amira Abase, 15, and Kadiza Sultana, 16 – left Bethnal Green Academy in east London on the last week of February for Turkey, reportedly to cross into Syria to join extremists, possibly Daesh – the Arabic-language acronym for the Islamic State of Iraq and the Levant, also known as ISIL.

The British government estimates that as up to 600 people have left the U.K. to go to Syria and Iraq.

More than 200 people were arrested last year on terrorism charges, according to British police.