US intel warns of potential terrorist threat at gatherings after Moscow attack ISIS claimed responsibility for the attack in Moscow that killed at least 144.

(ABC) Law enforcement officials expressed concern that radicals in the U.S. might respond to ISIS calls for similar attacks in the wake of last month’s deadly terrorist attack at a concert hall in Moscow.

The U.S. intelligence bulletin warns that ISIS operatives worldwide and so-called “lone wolves” might respond to recent statements from the terrorist group touting the attack in Russia and encouraging more attacks on public venues — even if the individuals are not members of ISIS.

Russian investigators said the March 22 attack in Moscow’s Crocus City Hall killed at least 144 people, including three children, and injured at least 550 others.

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