More than 140 million Russians yesterday observed a <a href="https://www.thenationalnews.com/world/2024/03/24/day-of-mourning-in-russia-after-moscow-concert-hall-attack-in-pictures/" target="_blank">national day of mourning</a> following Friday’s murderous attack on a <a href="https://www.thenationalnews.com/world/2024/03/24/recriminations-fly-as-russia-reels-from-deadliest-isis-attack-in-europe/" target="_blank">Moscow</a>-area concert hall that claimed over 130 lives. The shaky mobile phone footage of gunmen opening fire on defenceless civilians going about their business is chillingly reminiscent of similar mass-casualty attacks, such as those in Paris in November 2015 and Istanbul’s Ataturk Airport in June 2016 to name but a few. The indiscriminate and merciless cruelty of the attack has rightly drawn condemnation from around the world. The <a href="https://www.thenationalnews.com/uae/2024/03/23/moscow-attack-uae-leaders-send-condolences-to-president-vladimir-putin/" target="_blank">UAE has lent its voice to this expression of outrage</a>, reaffirming its “permanent rejection of all forms of violence and terrorism aimed at undermining security and stability in contravention of international law”. On Saturday, the Emirates lit up some of its most high-profile landmarks in the colours of the Russian flag, a powerful show of solidarity with the <a href="https://www.thenationalnews.com/world/2024/03/24/day-of-mourning-in-russia-after-moscow-concert-hall-attack-in-pictures/" target="_blank">victims of the attacks</a>. Understandably, the sense of shock is palpable. However, for many people living in other parts of the world, extremist violence is a constant threat. ISIS and other organisations that share its fanatical ideology are active – daily – in Afghanistan. In 2023, neighbouring Pakistan suffered its worst terrorist violence in the past six years, with extremists killing about 500 civilians and a similar number of police and soldiers in a series of attacks. Several countries in Africa’s Sahel region have long been plagued by insurgents who take aim at civilians as much as they do their military opponents. The Middle East also suffers frequent and painful reminders of extremists’ ability to strike terror; less than three months ago, two ISIS suicide bombers in Iran killed dozens of people marking the anniversary of the death of military commander Qassem Suleimani. Iraq and Syria have been the two countries that have suffered the most from ISIS, when it overran major cities like Mosul and subjected its people to untold horrors. ISIS has also established itself in Central Asia, with an October 2023 report from the Hudson Institute, a US think tank, stating militants there “have taken on an increasingly visible role in ISKP’s [ISIS Khorasan Province’s] local, regional and international activities”. The relative decline in mass-casualty attacks in the US, Europe and Russia has not been due to any lack of intent by ISIS and their associates. The killers’ determination must be met by similarly determined action from national governments and international law enforcement. Despite the heinous nature of the attack on Crocus City Hall, now is the time for cool heads and a concerted effort to hold all those responsible for the attack to account. Russia’s people deserve to see a clinical investigation, thorough police work and intelligence sharing. One thing that does not help this volatile situation is <a href="https://www.thenationalnews.com/world/europe/2024/03/24/russian-accounts-of-moscow-attack-a-smokescreen-says-uk-minister/" target="_blank">speculation</a>. The reality is that ISIS and its offshoots do not need a grand conspiracy to kill civilians; their reign of terror across parts of the Middle East is evidence of this. A rush to judgment can also lead to political confusion and complicate the security response. The threat from ISIS and other groups knows no borders. Sadly, the current level of mistrust between the West and <a href="https://www.thenationalnews.com/tags/russia/" target="_blank">Russia</a> is such that a question mark hangs over the kind of international collaboration and intelligence sharing that is essential for governments to thwart plots such as that which unfolded in <a href="https://www.thenationalnews.com/world/2024/03/23/gunman-open-fire-in-moscow-concert-hall-in-pictures/" target="_blank">Moscow</a> on Friday night. Russian President Vladimir Putin has said that <a href="https://www.thenationalnews.com/world/europe/2024/03/22/moscow-concert-attack/" target="_blank">11 people have been detained</a> in connection with the attack so far, including the four gunmen. This is an opportunity for investigators to get to the bottom of Friday’s grotesque violence, but the work should not stop there; there should be a renewed and practical determination for international law enforcement to work more closely together. The violence that took place in <a href="https://www.thenationalnews.com/world/europe/2024/03/23/115-dead-during-shooting-in-moscow/" target="_blank">Moscow</a> was a crime – and criminals must be brought to justice.