What is known after Islamic State group claims responsibility for massacre at a Moscow concert hall

By VANESSA GERA
Associated Press

WARSAW, Poland (AP) — An Islamic State group affiliate has claimed responsibility for an attack on a suburban Moscow concert hall that killed at least 133 people. The U.S. says it has evidence backing up the claim that IS did in fact carry out the bloody massacre Friday, the worst attack in Russia in years. But that didn’t stop Moscow and Kyiv from pointing the finger at each other as the war in Ukraine rages on. Much remains unknown about the attack, including why the Islamic State group would have carried out the attack and whether it signals a resurgence of the group.