The series of bombings on Easter Day in Sri Lanka, targeting worshipers gathered to celebrate the most significant day on the Christian calendar, was a sobering reminder of how vulnerable the world remains to terrorist actors bent on killing innocents and fermenting hatred.

The coordinated bombings in Sri Lanka collectively amounted to one of the deadliest terror attacks in modern history, the kind of thing most Americans feared they would see more of in this country following the attacks of Sept. 11, 2001. It has been a remarkable achievement of our national security forces to prevent another mass killing in the years that have passed since, because surely there are those who would strike if given the opportunity.

In the aftermath of the Sunday bombings the death toll climbed past 320 as the number of those who died on Easter was updated and more victims succumbed to the wounds they suffered in the attacks on three Christian churches and three hotels.

The mass killings were a decade removed from the terrible and violent ethnic-based civil war that plagued the country for 25 years and left more than 80,000 dead. Yet while horribly familiar to Sri Lankans, the Easter Day attacks do not appear directly tied to the animosities spawned by that long, internal war.

In recent years, the Asian nation has seen a renewed increase in attacks on the minority Muslim population by militant Buddhist monks. Yet the Easter Sunday bombings appeared primarily targeted at another minority population, Christians, by Islamic extremists. The nation is roughly 70 percent Buddhist, 10 percent Muslim and 7 percent Christian.

The early stages of the investigation showed that social media was again used as a platform to generate the level of loathing and delusion necessary to convince young men that there is something noble in blowing themselves up to kill others whose only “fault” is having different beliefs.

More evidence that hate begets hate — not that any further proof is necessary — were indications that the attacks were, at least in part, a retaliation for the killing of 50 people last month at mosques in New Zeeland by a lone gunman.

It appears the attackers were all Sri Lankans, but some had traveled abroad where they may have coordinated with international terrorists in planning the large-scale terror attack.

Sri Lankan security officials pointed to a small, radical Islamist group called the National Thowheeth Jama’ath, but there were also indications it worked with the Islamic State. On Tuesday the Islamic State claimed responsibility.

While attacks on the United States and European nations have a higher propaganda and recruitment value for these terror networks, third-world nations are softer and far more vulnerable targets. In many Middle East nations such attacks are terribly routine.

Reporting that these attacks may have been prevented, or at least reduced in scale, is alarming. Warnings of a possible impending attack were not acted on by Sri Lankan leaders. This should give pause to our own national security agencies and to the administration of President Trump.

In the days leading up to the attacks, domestic security forces, with assistance from India, had indications that plotting was underway for a mass attack and that Catholic churches appeared to be targets. According to the New York Times, security forces knew of specific individuals involved with the plotting, individuals who ended up carrying out the actual attacks.

Why this information was not acted on to round up those tied to the plot or to issue warnings and increase security at Easter services is not yet clear. Some of the speculation points to deep divisions within the government that sowed suspicion among elected leaders and inhibited a healthy sharing of information. Sound familiar?

While the Department of Homeland Security apparatus is this country is far, far more robust than that of Sri Lanka, the recent turmoil in leadership at the agency, with some positions vacant and others filled with acting officials, is a situation that needs to be rectified as soon as possible.

The United States must be at the top of its game when it comes to addressing foreign or domestic security threats. This means that rebuilding the management of DHS, with qualified leaders approved by the Senate, must be a priority.

The Day editorial board meets with political, business and community leaders to formulate editorial viewpoints. It is composed of President and Publisher Timothy Dwyer, Executive Editor Izaskun E. Larraneta, Owen Poole, copy editor, and Lisa McGinley, retired deputy managing editor. The board operates independently from The Day newsroom.