Russia says ISIS was behind deadly concert attack, more than 20 arrested
![Russia says ISIS was behind deadly concert attack, more than 20 arrested](https://media-cldnry.s-nbcnews.com/image/upload/t_fit_1500w/rockcms/2024-03/240325-moscow-concert-hall-attack-mn-0838-f4ed89.jpg)
Russia has arrested more than 20 people in connection with an attack claimed by Islamic State that killed more than 140 people at a concert hall near Moscow in March, the head of the FSB security service said on Friday.