Boko Haram Suspected in Deadly Suicide Bombing at Nigerian School CONAKRY, Guinea - A suicide bomber disguised as a student detonated a bomb at a boarding school in northern Nigeria on Monday morning, killing nearly 50 boys who were between 10 and 20 years old, officials and witnesses said. The bomber was wearing a school uniform when he appeared at the morning assembly at the Government Senior Science Secondary School in Potiskum, according to Mohammed Abubakar, a local journalist who had just returned from the scene of the bombing. When the school prefect asked the bomber why he was not wearing the school's badge, he knelt down and detonated the bomb, Mr. Abubakar said. Afterward, witnesses said, the school was a chaotic scene of dead and maimed children, and the local hospital was packed with the wounded. Northern Nigeria has long been crippled by an Islamist insurgency, and the militant group Boko Haram has targeted non-Koranic schools for at least the last three years, killing dozens of students and kidnapping hundreds of others. Monday's bombing, which also wounded nearly 80, was one of the worst such attacks to date. In Potiskum alone, a major market town on the principal east-west axis in Nigeria's north, Boko Haram is believed to have attacked about 10 schools. In just over a year, five other schools in surrounding Yobe State have been assaulted by fighters believed to be members of the group. In February, at least 40 were killed at a boarding school in nearby Buni Yadi; in July of last year, 42 students were killed in an attack at a government school in a village near Potiskum. Boko Haram did not claim responsibility for Monday's bombing - it rarely does for individual attacks - but it has made what it calls "Western education" a particular focus of its bloody campaign against civilians and soldiers. Despite the repeated school attacks and multiple student deaths, Nigeria's military has not been deployed to guard the schools of the north, and there was no military presence before the blast at the Potiskum school Monday, Mr. Abubakar said. The school was "not safe. It is porous," he said, adding that even the school gate was broken. A resident who lives nearby, Yahaya Wakili, said there is "no fencing," adding that "Everybody can come inside the school." The only protection came from a few local guards armed with sticks, said Mr. Abubakar said. Parents who gathered at the school after the bombing angrily told the military to leave, saying they "no longer had confidence" in the soldiers "because they were not able to protect their lives and property," said Mr. Abubakar. Some news reports suggested rocks were thrown at the soldiers. Reflecting a rising tide of criticism against the Nigerian government, which has ceded large sections of territory to the Islamist militants in the northeast this year, the governor of Yobe State issued a strongly-worded statement Monday saying it was "not just enough for the federal government to condemn the almost daily rounds of violence." Instead, he said "urgent action" was needed. Boko Haram Kidnapping Tactics, Explained In Nigeria, more than 200 schoolgirls have been held captive since last April. Some background information on the Islamist group that has been trying to topple the country's government for years. Video by Natalia V. Osipova on Publish Date May 9, 2014. Photo by Sunday Alamba/Associated Press. It was just before 8 a.m. on Monday, and the students at the 2,000-student school had gathered for morning assembly. A slight man of around 25 wearing the school's uniform appeared. "He entered the assembly ground," said Mr. Wakili. They were waiting for the principal and the other teachers. According to the accounts, the man was carring a heavy bag, prohibited under school rules. He told the prefect it was for carrying his books. A student who was there, Mohammed Musa, said, "We were at the assembly ground waiting for our teachers to address us for the beginning of the week, and suddenly I heard a very heavy sound." The blast resounded throughout the neighborhood. "It was very, very loud," said Mr. Wakili. Abdulkareem Adam, another student, described "so many dead bodies littered on the ground." Mr. Abubakar, the local journalist who went to the school immediately after the blast, said, "I saw many wounded schoolchildren." He described ghastly injuries and "people running away with wounds." The Nigerian government issued a statement condemning the bombing. But the blast is likely to raise further questions about the efficacy of a military counterinsurgency campaign that appears to be floundering in the face of an intensifying Boko Haram onslaught. The Islamist group has made substantial gains in the three weeks since Nigeria officials announced that it had reached a supposed cease-fire with it.