Human-rights groups say anywhere from 200 to 500 Christians were killed by Muslim herdsmen in Nigeria over the weekend. The attacks took place near the central city of Jos and were apparently retaliation for attacks on Muslims in January. As the main city on the fault line between Nigeria’s Muslim north and Christian south, Jos has long been a hotbed of religious violence. Victims from the sectarian violence were placed in mass graves in central Nigeria. Survivors recalled gruesome stories of the previous day’s events. The attackers had placed nets and traps outside the huts of villagers and attacked them with machetes. Unlike previous clashes, this year's attacks have been planned out, leaving hundred dead including babies, the elderly, and anyone else unable to flee.