An estimated 30,000 Fulani armed militants operate across Nigeria and killings Christian in the country, says the United States Commission on International Religious Freedom.

“An estimated 30,000 Fulani militants likely operate across the country, traditionally concentrating in the country’s northwest, then migrating down through the Middle Belt, and becoming increasingly active in the South,” the USCIRF report released in May stated. “Violence by Fulani militants caused the highest number of deaths among all religious communities in Nigeria over the last year as compared to attacks by organised insurgent groups and criminal gangs.”

The report examined the role of Fulani militants in deteriorating religious freedom conditions in Nigeria by explaining Muslim and Christian communal dynamics and providing examples of recent and ongoing religious freedom violations by violent Fulani actors.

“In recent years, armed actors from a Fulani ethnic background have perpetrated some of the most visible and deadly attacks on religious communities—often but not exclusively against Christians—in Nigeria,” the report stated. “While many Fulani militant groups wage independent attacks, others periodically coordinate with a wide range of other actors, from conventional bandit gangs seeking financial enrichment to recognised terrorist organisations that espouse a violent interpretation of Islam.”

According to the report, each group consists of between 10 and 1,000 members. While these militants do not share a centralised leadership, some collaborate on attacks.

“Fulani assailants have not spared Muslims, raiding herders’ cattle and violently attacking non-Fulani Muslim communities. Furthermore, many militants have targeted Christian communities in the Middle Belt and, increasingly, the South, burning homes and churches as well as kidnapping, raping, and murdering,” the report explained.

It added, “Militants often coordinate via radio and utilise motorcycles and automatic weapons, rapidly hitting several targets at once in rural, isolated areas. They often wield machetes and descend on vulnerable communities during the night, eliciting terror as a way to force victims to quickly leave and to achieve greater control of desired land.”

The Fulani militants were declared the fourth deadliest terrorist group in the world by the Global Terrorism Index in 2014.