article_snippet: Shamima Begum, Amira Abase, both 15, and Kadiza Sultana, 16, are thought to have reached the terror group's de facto capital Raqqa after fleeing the UK to join a friend last month.
article_snippet: Amira Abase, Shamima Begum and Kadiza Sultana  are understood to be in the ISIS stronghold of Raqqa .
article_snippet: are now believed to be in Raqqa, Islamic State’s stronghold and scene of some of Raqqa most barbaric atrocities.
article_snippet: Islamic State seized large swathes of land last June, including territory close to the Turkish border.
article_snippet: The U.S.-led coalition is using mostly air power in an attempt to push the Sunni militant group back.
highlights_snippet: Trio understood to be in the terror group's de facto stronghold of Raqqa .
  