"Putin Vows Justice for Moscow Concert Massacre, Alleged Attackers Arrested"

Russia has arrested all four gunmen suspected of carrying out a shooting massacre in a concert hall near Moscow, with President Vladimir Putin vowing to track down and punish those behind the attack. The death toll stands at 133, with 11 people detained, including the four gunmen. While Islamic State claimed responsibility, there are indications of a potential Ukrainian link, which Ukraine vehemently denies. Putin has pledged to punish all those responsible for the atrocity, and the international community has expressed sympathy and condemnation for the attack.