British police are trying to trace the movements of three teenagers who are believed to be travelling to join Islamic State fighters in Syria.

Three girls, two aged 15 and one 16, flew to Turkey on Tuesday without their parents’ knowledge. The three are thought to be friends with a fourth girl who travelled to Syria in December.

“What we do know is they’re all British girls,” Nico Hines, the London editor of the Daily Beast, told CTV News Channel. “All three of them are said to speak with a strong London accent. These are proper British girls.”

Two of the girls, Shamima Begum and Kadiza Sultana, are pupils at the Bethnal Green Academy in London.

“Even more bizarrely, they’re said to be really smart. They’ve done really well at school,” Hines said. “And it’s just one of these great mysteries – why are these people convinced to go?”

Hines said, upon arrival, women who join the Islamic State are thought to become part of a team of recruiters who try to lure other young recruits online.

Police and the teens’ families are attempting to reach the girls through social media, urging the girls to return home.