Until the other day, few Americans could likely find Sri Lanka on a map, nor even dimly remember its British colonial name, Ceylon. But the Indian Ocean nation flashed across news screens over the Easter weekend with a highly sophisticated and lethal series of bombings across the island nation of some 20 million.

The attacks were probably inspired, encouraged and possibly assisted by the so-called Islamic State, and — on a population-adjusted basis — amounted to a 9/11-level attack on a multicultural and multireligious state, killing more than 320 people thus far across nine sites, with hundreds more wounded.

The attacks were conducted with suicide bombers and improvised explosive devices, executed at a level that seems far beyond the capabilities of the Sri Lankan radical Islamic splinter group Nations Thawahid Jaman that has claimed responsibility. Previously, the group had specialised in comparatively benign defacement of Buddhist statues — 70 per cent of Sri Lankans are Buddhists.

The idea that this organisation could suddenly plan and conduct a nationwide, precisely timed series of nine bombings seems highly unlikely. Thus suspicion grows that Isis was involved at an operational level — a modus operandi associated with its increasing globalisation.

Welcome to Terrorism 3.0. A way to think about the evolution of global terrorism is a bit like new computer software releases — improving over the decades. Terrorism 1.0 in the modern era was in the 1980s: Red Brigades of Italy, Baader-Meinhof gang of Germany, Sendero Luminoso of Peru and the Palestinian Liberation Organisation, among others. They were disconnected and nationally focused, by and large.

Terrorism 2.0 emerged after the fall of the Berlin Wall, and is embodied by the rise of radical groups including al-Qaeda, al-Shabab, Boko Haram — essentially regional groups with sporadic international reach. In Terrorism 3.0, we see the Islamic State — a globally dispersed, highly lethal, financially capable, deeply innovative organisation.

While the West has been able to compress its occupation of territory, effectively knocking it out of a geographical caliphate in Iraq and Syria, it has morphed into an internet-based organisation that continues to conduct highly sophisticated attacks and establish cells across the globe.

In a business context, the Islamic State is like an international conglomerate that has untethered itself from the costly, time-consuming business of operating retail bricks and mortar. A global map showing Isis-inspired or conducted attacks is revealing, far beyond anything al-Qaeda has managed. And, no question, it will continue to conduct lethal attacks, seeking over time to obtain weapons of mass destruction — chemical, biological, radiological and cyber.

Even as the US has begun to pivot away from counterterrorism operations to face new challenges in global great-power politics from China and Russia, the Islamic State has no intention of calling a time out or ceasing operations despite the loss of its territory. So, the question remains, how do America and its allies in Europe and beyond address this continuing threat, recognising — as the newest US National Security Strategy does — that more resources must be devoted to “high-end” potential conflict with near-peer competitors such as China and Russia?

To deal effectively with the evermore ambitious groups and their emerging internet-based strategy, we will need three key lines of effort. The first is to continue to internationalise the fight against the Islamic State. The coalition against Isis has more than 70 nations and international organisations participating at one level or another, and was a legacy of the Obama Administration picked up by the Trump team.

Unfortunately, the key architects — retired General John Allen and diplomat Brett McGurk — have been discarded by Trump. We need to appoint new professionals to guide this effort, and for the US to reassert itself as the leader. The message to the international community should be that the kinetic victory in Syria is not “mission accomplished”, but rather signals a need to redouble our efforts at co-ordinating and sharing intelligence to respond to moves by Isis.

Second, we will need a better level of inter-agency co-operation, particularly in intelligence, military action, diplomacy, and developmental activities — USAid and other governmental groups. Our efforts are still highly stove-piped in terms of counterterrorism. The National Counterterrorism Centre is a good inter-agency fusion cell, but needs more real convening and operational power to be truly effective. A good start in the US would be developing a national strategy to eliminate the Islamic State and other affiliated, global terror organisations, written and executed in parallel to other official strategies such as homeland security, cybersecurity and missile defence.

A third key ingredient is private-public co-operation. This includes working, and sharing intelligence to some degree, with private non-governmental organisations such as Interpol, the Red Cross and Red Crescent, Médecins sans Frontières, Operation Hope and other entities that try to address base conditions of poverty and disease that help to create recruiting opportunities for terrorist organisations. It also includes working with the tech giants — notably Google, which has done signal work in this space — on depriving terror organisations of access to the social networks. A new book by Peter Singer and Emerson Brooking, Like War: The Weaponisation of the Social Networks, outlines this well.

Terrorism 3.0 will continue to spread like a global cancer, enhanced by the accelerative power of the internet. We need not only classic hard-power solutions as we saw in Syria and Iraq, but a combination of other 21st-century tools as well if we are to contain and eventually conquer it.

• James Stavridis is a Bloomberg Opinion columnist. He is a retired US Navy admiral and former supreme allied commander of Nato, and dean emeritus of the Fletcher School of Law and Diplomacy at Tufts University. He is also an operating executive consultant at the Carlyle Group and chairs the board of counsellors at McLarty Associates