A terrorist attack occurred at a concert hall in Russia.

By: AHSAN MUMTAZ

– ISIS claimed responsibility for the attack.

– The attack resulted in at least 133 deaths and hundreds of injuries.

– Four suspects were apprehended near the Ukrainian border.

– Russia believes the attackers intended to cross into Ukraine.

– ISIS's claim of responsibility was confirmed by the United States.

– This is the most lethal terrorist attack in Russia in recent years.

– This is the most lethal terrorist attack in Russia in recent years.