turkish authorities stop them as they tried to enter syria. it's believed they were planning to join the group isis. their return to london suggests greater cooperation in the battle against isis. >> reporter: british counterterror officials learned that two 17-year-old males were traveling from northwest london planning to go to syria via turkey. so british officials called up their turkish counterparts and the two teenagers were stopped in turkey, along with another 19-year-old male who was traveling with them. that happened on friday. all three were deported back to the u.k. late sudden night. now this quick work stopping them in turkey and returning them back here to the u.k. stands in stark contrast to the three teenage british schoolgirls who traveled from east london also to turkey. then spent several days in turkey before they were able to cross undetected into syria. that happened several weeks ago.