Somalia’s al-Shabaab was the deadliest terrorist organization in Africa in 2016, ending Boko Haram’s four-year reign.

The Somali terror group killed 4,281 people in 2016, with a high concentration of attacks taking place in the capital Mogadishu, according to new data compiled by Armed Conflict Location & Event Data Project (ACLED) and the Africa Center for Strategic Studies, and first reported by Quartz. Boko Haram killed 3,499.

Since forming in 2006, al-Shabaab has carried out more than 360 attacks in Somalia. The terror group’s resiliency has proved an obstacle for the country’s new president and worsened its numerous humanitarian issues. Recently, the U.S. military signaled a push toward greater counterterrorism action against al-Shabaab in Somalia, including authorizing unilateral action for ground operations and the use of airstrikes. In April, the U.S. deployed dozens of troops to assist the Somali government’s national army in its fight against the Islamist extremist group.

The rise of al-Shabaab parallels the declining capacity of Boko Haram to maintain territorial control, which has been further exacerbated by mounting military pressure from the Nigerian government and an internal split into two factions.

“We have seen Boko Haram in a declining capability to gain such ‘control’ and relying on, for example, more suicide bombers,” said Jasmine Opperman, the director of Southern Africa Operations at Terrorism, Research & Analysis Consortium (TRAC).

Boko Haram remains a major terror threat throughout Africa’s Lake Chad region, which includes Nigeria, Niger, Chad, and Cameroon. In the past six years, al-Shabaab and Boko Haram accumulated a combined body count far higher than that of ISIS and al-Qaida combined, according to ACLED and the African Center for Strategic Studies. Between 2010 and 2016, the two terror groups racked up more than 47,000 fatalities while ISIS, al-Qaida in the Islamic Maghreb, and other al-Qaida linked groups totaled 9,236.

The total number of terror attacks on the African continent has increased by 1,000 percent in the past 10 years, according to a report by the Mo Ibrahim Foundation. The foundation found that the uptick is largely fueled by declining economic prospects for African youth, as well as unemployment and social isolation.

Between 2006 and 2015, terror attacks rose from about 100 per year to nearly 2,000, according to data from the National Consortium for the Study of Terrorism and Responses to Terrorism at the University of Maryland. And in documents obtained by VICE News, Donald Bolduc, the U.S. Army general running special operations command in Africa, warned that “Africa’s challenges could create a threat that surpasses the threat that the U.S. currently faces from conflict in Afghanistan, Iraq, and Syria.”