In the United Kingdom, reeling from Monday’s horrific and monstrous suicide bombing in Manchester Arena that killed 22 mostly young pop music fans, officials have raised the terrorist threat level from “severe” to “critical” — indicating that they believe another terror strike is imminent, and that the perpetrator, Salman Abedi, was not acting alone. In addition, armed soldiers will be deployed on British streets. For ordinary Britons as they go about their daily business, the sight of troops carrying assault rifles will be a stark and frightening reminder that their lives have now changed while the risk of terror is high — and it is a sight that residents of France have had to become accustomed to in the past year.

While increasing terror threats and putting armed troops on the streets is an obvious measure to reassure a jittery citizenry, security measures alone will not overcome the existential threat posed by extremists and terrorists. Yes, surveillance, intelligence and the sharing of information by security and intelligence agencies, at levels that transcend national boundaries, can provide critical data on those who are driven to the darkest corners of murderous political and sectarian extremism. But to truly defeat these elements, you must also know your enemy. In effect, the authorities must identify extremist elements and ideologies, and those who propagate them, thinking that it is acceptable to kill and maim children watching a pop concert. Whether it be at places of worship, community centres, in classrooms or cultural gatherings, in social groups or on social media, those who propagate, profess, procure or pander to extremist ideologies, need to be rooted out — and every tenet of their ideology disparaged, debunked and destroyed.

The events of these past years, whether in the Middle East, United States, UK, Germany, Belgium, Paris or Manchester, scream that there must be zero tolerance everywhere for the ideologies of extremists. And those who propagate such vile hatred must neither find sanctuary on social media nor be harboured at places of worship or in gatherings where their influence will mislead malleable and ductile minds.

There is a broad agreement between governments, whether in the West or the Middle East, that reason must prevail over radicalism. But rooting out extremists, their ideologies, and those who willingly or surreptitiously support such thinking, requires more than tacit agreement — it requires concerted effort and genuine commitment to fight extremism and terrorists on every front. It is a transnational and pan-religious fight, one that every government must wage.