GUSAU, Nigeria—Hundreds of Nigerian girls abducted last week from a boarding school in the country’s northwest have been released, a state governor said Tuesday, as the West African nation faces a spate of school kidnappings. The girls, ages 10 and up, dressed in light blue hijabs and barefoot, packed into Zamfara state’s Government House conference room. They appeared calm, chatting to one another as they sat in long rows while journalists photographed them. They will receive a medical checkup before being returned to their parents. Zamfara Gov. Bello Matawalle said that 279 girls had been freed after being abducted from the Government Girls Junior Secondary School in Jangebe town on Friday. The government last week said 317 had been kidnapped. It was not clear if the higher number was an error or if some girls were still missing. “Alhamdulillah! (God be praised!) It gladdens my heart to announce the release …