The U.N. Children’s Fund in Nigeria said at least 1 million Nigerian children could miss school this year because of insecurity, as schools in the north of the country have been targeted by armed groups in a series of mass kidnappings for ransom. UNICEF Nigeria said Wednesday the country had recorded 20 school attacks this year alone, and 1,436 students have been abducted. The report also showed that 16 students have been killed, and 200 remain missing. As schools across the country began opening this week for a new semester, more than 37 million students are due back at schools. But officials reported low attendance in attack-prone areas like north central Kaduna state. In the capital, authorities pushed back the resumption date to September 19 without giving a reason. Ransom-seeking criminal gangs began targeting schools in northern Nigeria late last year. Amnesty international says hundreds of schools there have been closed as a result.