Moscow Shooting: Russian President Putin Declares National Mourning, Claims Ukraine Involvement

Russian President Vladimir Putin addressed Russians on Saturday and declared Sunday a national day of mourning for the victims of the attack on a concert hall in Moscow. He also said that additional security measures have been imposed throughout the country and suggested that Ukraine was linked to the attack on a concert hall on the outskirts of Moscow that killed 133 people, according to Russia's top state investigative agency.