Hundreds of militants believed to be members of the Islamist group Boko Haram attacked an army barracks in Nigeria March 14, the latest event in the country’s years of violence from the group. The army said it had repelled the attack on the barracks in the northeastern city of Maiduguri, in Borno state. “They set many houses on fire and killed innocent people,” Jamila Yusuf, a local resident, told the Nigerian newspaper Daily Trust. A military spokesman said the attack was an effort to free fellow members who were imprisoned there, the BBC reports. One military source told Agence France Presse that the attack freed dozens of suspected militants, though Nigeria’s defense ministry did not confirm or deny the report. Eyewitnesses said there were deaths on both sides. The military said attackers suffered “heavy casualties,” while four soldiers were wounded. In Adamawa state, also in northern Nigeria, Boko Haram militants killed 37 in an attack on a town and neighboring villages Feb. 27. Two days earlier, the group attacked a boarding school in Yobe state, to the west of Borno. At least 29 students were killed at the secondary school. According to the BBC, the militants told female students were gathered together and told to abandon their education and to marry. Boko Haram, which means “Western education is sinful,” launched an uprising in 2009 and hopes to impose sharia law on Nigeria. It has targeted security forces, politicians, Christian minorities, and moderate Muslims in Nigeria’s predominantly Muslim north. In February, militants killed Mohammed Awwal Albani, an Islamic scholar, after he said Boko Haram’s actions were un-Islamic. Boko Haram’s attacks have killed thousands since 2009; according to the BBC, they have killed 500 in 2014 alone. The U.N. estimates that the attacks have led to more than 470,000 internally displaced persons in Nigeria. In January Boko Haram members attacked a Catholic parish during Mass, firing guns into the congregation, setting off explosives and taking hostages. In February, Archbishop Ignatius Kaigama of Jos lamented that government authorities are unable to stop the violence. He said he suspects that groups outside Nigeria are offering “sophisticated assistance” to Boko Haram. The U.S. recognized Boko Haram as a foreign terrorist organization in November 2013, after a lengthy advocacy effort from human rights and Christian groups.