Just over a year ago, Congolese troops found a book written in Arabic on the body of an enemy combatant.

The book was from the Islamic State’s Research and Studies Office, a department of the terrorist group’s now-defunct state in Syria and Iraq that issued doctrinal texts buttressing its brutal worldview. The discovery of the book in the spring of 2018 was among a number of clues indicating that the Islamic State, also known as ISIS, was trying to establish a toehold in the lawless jungles of eastern Congo.

On Thursday, the Islamic State’s news agency claimed the group’s first attack in the Democratic Republic of Congo, stating that its soldiers had assaulted a military barracks in the area of Beni, killing eight people.

The attack took place in a region troubled by violence in a part of the world long outside government control, the kind of terrain that has proved to be fertile ground for ISIS. If the group succeeds in planting its flag here, it would not only expand its reach into a new part of the continent, but it would also do so far outside the grasp of international forces.