( CNN ) Three teen British girls suspected of traveling to Syria to join ISIS appeared on surveillance video in Turkey before they went to their destination . Images show the teens boarding a bus in Istanbul , Turkish HBR television reported . It 's the first sighting of the girls since they left London almost two weeks ago . Authorities have said they have no reason to believe the girls are still in Turkey and believe they have crossed into neighboring Syria , parts of which have been taken over by Islamist terror group ISIS . The three east London classmates -- Shamima Begum , 15 ; Kadiza Sultana , 16 ; and Amira Abase , 15 -- boarded a Turkish Airlines plane from London 's Gatwick Airport to Istanbul on February 17 . A British counterterrorism officer said police had tried to reach out to the girls using the Turkish media and social media to persuade them to return home . The girls ' parents have also publicly begged for them to come home . Days before they left for Turkey , at least one of the girls allegedly contacted a young woman , Aqsa Mahmood , who left her home in Scotland to travel to Syria in 2013 and is accused of trying to recruit others via social media . An attorney for the Mahmood family said the family was `` surprised , horrified '' that the contact had not prompted police action `` because they understood that Aqsa 's social media content was being closely monitored by the security services . '' `` And the real concern that arises is that if a known member of ISIS who 's now a poster girl for ISIS , seen to be recruiting and spreading propaganda , is in touch with young people in our country -- that one would expect the courtesy of a knock on the door of these families , to advise them that their children may be on the cusp of radicalization or going off to Syria , '' Aamer Anwar said . The Mahmood family condemned their daughter 's actions , describing them `` as a perverted and evil distortion '' of Islam . But they also said the UK security services `` have serious questions to answer '' over their failure to intervene after one or more of the missing girls got in touch with her . Turkey has become the most traveled route for volunteers trying to join Syria 's many armed factions since an anti-government uprising erupted more than three years ago . Initially , Ankara maintained an `` open door policy , '' allowing hundreds of thousands of Syrian refugees to flee to safety in Turkey . Turkish border guards looked the other way , taking few steps to stop activists , volunteers and journalists from crossing into Syria . But with the rise of the ultra-violent Islamist group ISIS in Syria , the Turkish government increasingly came under criticism at home and abroad for not doing enough to stop jihadists from going through Turkey to get into Syria . Some critics have accused Ankara of actively supporting ISIS against rival Kurdish rebel groups , charges the Turkish government has angrily denied . Last year , the Turkish government showed CNN new barricades , thermal cameras and fences aimed at better fortifying the border . Historically , the Turkish-Syrian border , which runs more than 800 kilometers ( 500 miles ) , has been notoriously difficult for Turkish security forces to control . Before the Syrian civil war , both smugglers and Kurdish separatist guerrillas were known to operate illegally between the two countries . Turkish government officials have bristled in response to accusations that they are not stemming the flow of foreign fighters joining ISIS . Millions of tourists visit Turkey every year , where visas can be obtained upon arrival for citizens of many countries .
The teens are believed to have made it to war-torn Turkey . The girls ' parents publicly begged them to come home .