Recent reports of a large-scale massacre by Boko Haram in the northeastern state of Borno have served as a brutal reminder of the threat posed to Nigeria by the Islamist extremist group.

Yet, more than a week after the attack, there's little confirmed information about it. Reported death tolls vary wildly — one local politician told the BBC that 2,000 people had died, but others put the number at just dozens. On Monday, Nigeria's director of defense information said the number of those killed “has so far not exceeded about 150," including Boko Haram fighters.

Now, new satellite imagery obtained and released by Amnesty International and Human Rights Watch (HRW) appears to confirm that considerable damage occurred in the towns of Baga and Doro Gowon in Borno state.

The scale of the damage is remarkable. Adotei Akwei, managing director of government relations at Amnesty International USA, says that the images and other evidence suggested that the death toll was "certainly 700, if not 2,000 or close to it."

HRW estimates that in Doro Gowon, which houses a major military base, roughly 57 percent of the town, including thousands of residential and commercial buildings, have been destroyed. In the satellite image below, taken Jan. 10, red areas signify areas with fire burn scars, burned vegetation and damaged buildings. HRW says the majority of the damage probably occurred the evening of Jan. 3 and the morning of Jan. 4.


(Courtesy of Human Rights Watch)

HRW also estimates that 11 percent of Baga has been significantly damaged. The damage occurred predominantly in the south and east of the town and appears to have affected hundreds of residential buildings.


Baga on Jan. 10. (Courtesy of Human Rights Watch)

Separate imagery released by Amnesty offers comparative images of neighborhoods in Doro Bowan that appear to show significant damage at the start of the year. In one close-up, heavily burned areas can be seen on Jan. 7 that were not present Jan. 2. (Please note, in Amnesty's images, the red patches show vegetation.)


Images of Doro Gowon taken Jan. 2 and Jan. 7. (Courtesy of Amnesty International and Digital Globe)

Images showing neighborhoods in Baga shows similar destruction in that time period.


Images of Bagu taken on Jan. 2 and Jan. 7. (Courtesy of Amnesty International and Digital Globe)

A number of witness accounts have trickled out after the attacks. One man told Amnesty that he had personally seen about 100 people killed before he ran into the nearby forest. However, confirming such reports has proved exceptionally difficult. Nigerian troops have been fighting Boko Haram in the area, and it is still too dangerous to travel to. Militias attacked cellphone masts in the area several months ago, meaning most mobile phones have no connection.

Meanwhile, what little information comes from the Nigerian government is often treated with suspicion. The government has often been accused of playing down Boko Haram violence in a bid to appear powerful and competent ahead of next month's general election. To make matters worse, the military also has a controversial history in Baga. Community leaders told HRW that almost 200 locals were left dead during a 2013 military raid.

As such, the satellite imagery provides some much-needed hard evidence — Boko Haram's attack clearly caused large-scale destruction in Baka and Doro Gowon. It also probably left a significant human toll.

“These detailed images show devastation of catastrophic proportions in two towns, one of which was almost wiped off the map in the space of four days," Daniel Eyre, Nigeria researcher for Amnesty International, says. “Of all Boko Haram assaults analyzed by Amnesty International, this is the largest and most destructive yet.”