<p>Breaking a five-day silence over the probe, federal investigators also said foreigners were deliberately targeted, marking an ominous new tactic in Russia’s losing battle with extremism. </p>.<p>Islamist rebels from the Caucacus, a group of mountainous Russian provinces that are beset with an entrenched separatist insurgency, have been widely suspected in the attack at Domodedovo airport.</p>
<p>Breaking a five-day silence over the probe, federal investigators also said foreigners were deliberately targeted, marking an ominous new tactic in Russia’s losing battle with extremism. </p>.<p>Islamist rebels from the Caucacus, a group of mountainous Russian provinces that are beset with an entrenched separatist insurgency, have been widely suspected in the attack at Domodedovo airport.</p>