Russia said on Saturday it had arrested all four gunmen suspected of carrying out a shooting massacre in a concert hall near Moscow, and President Vladimir Putin pledged to track down and punish those behind the attack.
The militant Islamic State group claimed responsibility for Friday's rampage but there were indications that Russia was pursuing a Ukrainian link, despite emphatic denials from Ukrainian officials that Kyiv had anything to do with it.
Moscow regional Gov. Andrei Vorobyov said 133 bodies had been recovered from the rubble in 24 hours, and doctors were "fighting for the lives of 107 people." State TV editor Margarita Simonyan, without citing a source, had earlier given a toll of 143.