Russian authorities have arrested three individuals in Dagestan, North Caucasus, on suspicion of planning terrorist attacks. The arrests come in the aftermath of a deadly attack on a concert hall near Moscow, which claimed the lives of at least 144 people and left 551 injured. While the Islamic State group (IS) has claimed responsibility for the attack, Russian authorities attribute it to Ukraine. The recent arrests were made during an operation in Makhachkala and Kaspiysk, where weapons and an improvised explosive device were reportedly discovered. Additionally, three individuals from a Central Asian country were detained for allegedly planning a bomb attack in southwestern Russia.