At least 43 are dead -- 42 pupils and one teacher -- in the attack Saturday on the Government Secondary School in Mamudo town in Yobe, in northern Nigeria.
''We were sleeping when we heard gunshots. When I woke up, someone was pointing a gun at me,'' recalled 15-year-old student Musa Hassan, whose four fingers on his right hand were shot off when he raised his hands in instinctive self-defense.
''They burned the children alive," he said.
Others, witnesses said, were shot when they tried to flee the blaze.
Hundreds of the school's 1200 students were unaccounted for as they fled into the surrounding bush.
Nigerian President Goodluck Jonathan in May declared a state of emergency in Yobe and two other northern states, where militants have attacked dozens of schools since 2010 and killed more than 1,600.
The name Boko Haram translates to a call to ban Western education, and its attacks on schools are part of an effort to overthrow the government to establish an Islamist state in the mostly-Muslim northern Nigeria.