Westminster attack: messages at a vigil at Trafalgar Square on Thursday. Photograph: Jack Taylor/Getty

On Thursday morning, 18 hours after the Westminster attack, a large area around the Houses of Parliament remained cordoned off to everyone except poli(...)

Khadiza Sultana, Shamima Begum and Amira Abase passing through security at Gatwick Airport before flying to Turkey. Photograph: Metropolitan Police via The New York Times

The night before Khadiza Sultana left for Syria the teenager was dancing in her bedroom. It was a Monday during the February school vacation. Her n(...)

US president Barack Obama arrives to deliver remarks on countering violent extremism in Washington. Photograph: Jim Watson/AFP/Getty Images

US president Barack Obama called on Americans and more than 60 nations on Wednesday to join the fight against violent extremism, saying they had to co(...)