"Security Concerns Rise After Moscow Concert Hall Attack: France and U.S. Blame ISIS for 137 Deaths"

France and the U.S. believe that ISIS was behind the deadly concert hall attack in Moscow, while Russia suggests Ukraine's involvement. Four men, including a Tajik, have been remanded in custody on terrorism charges. Islamic State has claimed responsibility for the attack, but Russia has not publicly acknowledged this. President Putin accused "the Ukrainian side" of aiding the attackers, which Ukraine denies. France raised its terror alert, and President Macron offered cooperation to find the culprits. Unverified videos of the suspects' interrogations, showing signs of torture, circulated on social media. The U.S. and its European allies continue to support Ukraine in the ongoing conflict with Russia.