Amnesty International (AI) has released satellite images providing what it calls "indisputable and shocking evidence" of the scale of attacks on two Nigerian towns by Boko Haram militants last week.
The London-based human rights group said on January 15 that the images show the attacks on Baga and Doron Baga left more than 3,700 structures "damaged or completely destroyed."
AI cited witnesses, officials, and activists as suggesting that the Islamist militants shot hundreds of civilians in the offensive.
Thousands of people fled the violence, adding to the hundreds of thousands of internally displaced people and refugees.
AI Nigeria researcher Daniel Eyre said the images show "devastation of catastrophic proportions in two towns, one of which was almost wiped off the map in the space of four days."
AI says many towns and villages have fallen victim to a series of Boko Haram attacks which began on January 3.